A 6-blade turbine agitator with a diameter of 1.5ft is used to mix a solution with a viscosity of 10cP and a density of 95lb/ft 3. N=120rpm. Calculate the theo horsepower required if the tank is provided with 4baffles. 2hp. A double-flight helix impeller 3ft diameter and 3ft high is operating at 30rpm in a 3.2ft diameter tank. 85% full, 1000poise and 65lb/ft 3. Estimate hp requirement. 7hp A mixing tank set-up that follows curve 2 of Fig. 18-17 Perry, 8/ed. Is using vertical blades of H=3in. Width of each baffle. 6inches. A three-blade propeller is used to mix a fluid in the laminar region. Da=0.3m; N=1.5Hz. If flat two-bladed paddle D a=0.75m. What is N. 24rpm An agitation vessel is equipped with a turbine impeller having a diameter of 30cm. density=1000kg/m 3; viscosity=1x10-3 Pa-s; N=100rpm. What is NRe. 150,000 An agitator with a diameter of 2ft and a speed of 100rpm is mixing rubber-latex compound with a viscosity of 1250 poise and a density of 70lb/ft3. The N Re for the mixing operation is 5.56 An industrial mixing tank uses a 1.5ft diameter impeller operating at a speed of 120rpm. If 1000rpm, D a is 6inches.. Decreasing the shape factor, S 1, the ratio of the impeller to the tank diameter Da/Dt, when the baffles are few and narrow will increase the power requirement. Following the “standard” proportions in the design of a 6 -blade turbine agitator, if an impeller has a diameter of 20cm, what would be the recommended tank diameter and the depth of the liquid in the tank, in cm. 60cm, 60cm. For a pitched-blade turbine agitator, increasing the shape factor, S 2 defined as the clearance from the bottom of the tank, E/ D t, the power requirement will decrease. If the set-up given in prob. 18 is to mix a solution with a viscosity of 5 cP and a density of 65lb/ft 3, what will be the hp requirement if the speed of the impeller is 60rpm. 3.3hp. If the tank in Prob. 9 is unbaffled, what will be the power requirement. 0.42hp. If the viscosity of the liquid i s reduced by ½ due to heating of the liquid inside the tank, what will be the percentage reduction in the power requirement. 54%. In agitation, for N Re of 1000, the power requirement in a baffled tank is approx. 55% per 55% per cent higher/lower than in unbaffled tank. In the motion of the impeller blades against the liquid in the mixing tank, the force acting perpendicular to the surface of the impeller is referred to as drag force. In the use of turbines for low-viscosity liquids, rapid currents that destroys stagnant pockets occur. Near Near the impeller. It is desired to agitate a liquid having a viscosity of 1.5x10 -3Pa-s and a density of 969 kg/m 3 in a tank having a diameter of 0.91m. W= 0.0381. Calculate the required kW. 0.190kW One effective method of preventing vortex formation in a mixing tank where the shaft of the impeller is vertical, is to install baffles. Referring to prob.18, what will be the power requirement if the speed is increased to 80rpm. 7.8 hp Referring to prob.18, what will be the power requirement if the speed i s reduced to 10rpm. 2.3hp Relatively, the shape of the mixing tank, say cylindrical compared to a square or rectangular tank, has practically no effect on the power requirement. True.
The dimensionless number that describes the effect of wave motion on the surface of a liquid especia lly in agitation and mixing is expressed in terms of Froude of Froude number. The velocity components induced by the rotation of the impeller in the mixing process tends to induce the formation of vortex and swirling. These velocity components are tangential and radial. Using the data given in prob.15 and referring to Fig.18-17 Perry 8/ed, determine the power requirement if the mixing system is described by curve. 5. 5 hp. What will be the recommended volume of the solution to be charged in the mixing tank given in prob.18. Neglect the volume occupied by the mixer and baffles. 170ft 3 When blending two or more flammable liquids in a tank, it is appropriate to use jet use jet mixers. When strong vertical currents in the mixing tank is desired, it is best to use propellers use propellers When the NRe in a mixing tank is less than 10, the flow is considered laminar. In this range, the property that becomes unimportant in determining the power requirement is density of fluid.
20% Oleum means that in 100lb, there are 20lb of SO3 and 80lb of H 2SO4. 90% of the NH 3 entering an NH 3-oxidation unit is converted to HNH 3 and 10% loss of NH 3 is due to conversion losses, NO in the stack gases and miscellaneous losses. Kg of NH3 necessary to produce 60,000 kg of 62 wt% HNO 3 is 12,000. A 20% aqueous sol’n of Na2CO3 and 25% aqueous sol’n of Ca(OH)2 were reacted to produce caustic soda sol’n. Precipitate contains 5% H2O, 1% NaOH, 94% CaCO 3. The conc. Of NaOH sol’n p roduced is 10.97%. A cement clinker with the ff analysis: Cao=64%, SiO 2=21%, Fe2O3 and Al2O3. The MT of silica required for a 300-day operation per year is 20,000. A cement company uses 3000MT of gypsum a month. Portland cement, the MT clinker produced monthly by the cement plant is 75,000. A plant near Maria Cristina Falls is to manufacture NH 3 by using a stoichiometric mixture of N2 and H2. The moles of H 2 present in the mixture if 100mol of pure electrolytic H 2 is used is 84.95 moles. A water solution of molasses contains 10% by weight sucrose (C12H22O11). The weight percent of C 2H6O in the sol’n after 90% of the sucrose has been converted to C 2H6O by fermentation is 5.1%. An analysis of the gases entering the converter of an ammonia oxidation nitric acid plant indicates that the gases contain 0.066lb of NH 3 and 0.934lb of air per pound of gas. 1lb of the gas leaving the converter contains 0.00361lbmol of NO (no NO 2). % NH3 converted to NO is 93%. At a plant which produces H 2SO4 by the contact process, a large storage tank currently holds 100,000kg of 20% oleum, where 20% oleum means that in 100kg of material there is 20kg of SO3 dissolved i n 80kg of pure H2SO4. The weight percent H 2SO4 in the final mixture in the tank is 80.4%. Bauxite containing 61% Al 2O3 and 8% SiO 2 is roasted and dissolved in caustic soda to form a solution from which iron present is precipitated and filtered out. The cost of caustic soda needed to produce 1000kg of pure Al2O3 assuming 10% more than the t heo amount of NaOH needed is used. P used. P 6065. Bio-degradable detergents can be readily oxidized. Builders are added to soap to boost cleaning power.
Catalyst used in hydrogenation of oil is Nickel. Catalysts used in the manufacture of sulfuric acid by chamber and contact processes are respectively oxides of nitrogen and V 2O5 on a porous carrier. Cement mainly contains Cao, SiO 2 , Al 2O3. Coefficient of thermal expansion of glass is decreased by the addition of ZnO during its manufacture manufacture.. Contact process yields acid of higher concentration than chamber process. Cumene is the starting material for the production of phenol of phenol and and acetone Economics of “Solvay Process” depends upon the efficiency of ammonia recovery and size of plant. Enamels give Enamels give good glossy finish Essential oils are usually obtained using steam using steam distillation. Fat splitting catalyst is ZnO. is ZnO. Free alkali in toilet soap is less than that in a laundry soap. Function of thinner in a paint is to suspend pigments and dissolve film forming materials. Fusion of bauxite and Limestone and Limestone produces produces high alumina cement. Glauber’s salt is sodium is sodium sulfate decahydrate. Gypsum is calcium sulfate. Hydrazine is largely used as rocket fuel. In a liquid Cl 2 plant, chlorine gas with some H 2 gas is liquefied, with part of the Cl 2 made to form HCl, according to the ff diagram. The Cl 2 sent to synthesis plant in MT is 22.7. In contact process, SO 3, is absorbed in 97% H 2SO4 and not in water because water forms an acid mist which is difficult to absorb. In the lime soda process for caustic soda manufacture, lime is made to react with water and then with soda ash. The metric tons of lime that will be needed t o produce 100MT of 25% liquid NaOH is 31.21 MT. In the Lurgi coal gasifier large quantity of coal can be processed. Metallic soap is aluminum or calcium salt of fatty acids. Oil is a mixture of glycerides of fatty acids. Oxygen is produced by fraction of air using both Linde’s and Claude’s process. Permanent hardness of water is due to the presence of calcium and magnesium sulfates magnesium sulfates and chlorides. Plasticizers are added to paints to give to give elasticity and prevent cracking of the film Producer gas consists mainly of CO, CO 2 , N 2 , H 2. Rancidity of oil can be reduced by hydrogenation. Raw materials for “Solvay Process” for manufacture of the soda ash are salt, limestone, ammonia, and coke oven gas. SO2 is bubbled through hot sugar-cane juice to act as an acidifying agent Soap cannot be used with hard water because they form insoluble calcium soaps which precipitate. Solvent used for extraction of oil is methyl ethyl ketone. The catalyst used in the manufacture of DDT from chloral and chlorobenzene is oleum. The electrolytic reaction for the production of aluminum may be written as Al2O3 + 3/2 C 2Al + 3/2 CO 2, 235,000cal of energy (in the form of electricity) is consumed for the production of 2gmol of Al. Amount to be paid for elec. power per lb Al produced is P 0.066/lb Al. The main use of HCl is in the drilling of petroleum wells and pickling of steel sheets. The MT of CaCO 3 needed to produce 100MT of soda ash daily by the Solvay process is 93.34. Trinitro-toluene is an explosive.
Unsaturated oils compared to saturated oils have lower melting point and higher reactivity to oxygen. Using the data given below, the metric tons of rock phosphate (CaFCa4(PO4)3) needed to produce 6000MT of 90% purity superphosphate is 9530. Varnish does not contain pigment. contain pigment. Wax is a mixture of esters of polyhydric alcohols except glycerin. Which is the main reducing agent during the production of iron from iron ore in a blast furnace. CO Which of the ff is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants. SO2 Which of the following is a detergent. Alkyl detergent. Alkyl benzene sulfonate. Which oil is preferred for paint manufacture. Drying manufacture. Drying oil Widely used method for conditioning of boiler feed water is hot-lime soda process. Yellow glycerin is made into white, using activated carbon. Zeolite removes both temporary as well as permanent hardness of water by precipitating calcium and magnesium present in water as insoluble zeolites. Sodium chloride.
A continuous re-circulating aerobic biochemical process that keeps cells in suspended growth activated sludge process. A global treaty that aims to diminish and eventually phase out CFCs. Montreal protocol A global treaty that aims to protect human health and the environment from the persistent organic pollutants. Stockholm Convention A global treaty that aims to regulate emissions of greenhouse gases. Kyoto Protocol A neurological disease characterized by trembling, inability to walk and speak and even serious convulsions that can lead to death due to ingestion of mercury minimata. A phenomenon where a cold layer of air becomes trapped by a layer of warmer air above due to a lack of wind circulation or the presence of certain topographical features, such as mountains, resulting to air pollution being trapped in the lower, cooler layers of the troposphere. Thermal inversion A stack in an urban area is emitting 80g/s of NO. It has a n effective stack height of 100m. Estimate the ground level conc. At 2km downwind on the centerline. 63.7 microgram/m 3 A trace metal which causes Itai-itai disease is cadmium. A wastewater with a BOD/COD = 1 indicates that biological treatment is most practical. A water sample was analyzed to contain 150mg-L -1CO3-2 and 100 -L 1 HCO3-2 at a pH of 8.00 at 25 OC. Total alkalinity in terms of CaCO3 is 332ppm. Aeration of water is done to remove dissolved gases. An electrochemical process used in the removal of colloidal matter in wastewater through reduction of electrostatic charges surrounding the solids is called coagulation. Biomes are distinguished or identified by its dominant plant life. Calculate the theo oxygen demand (ThOD) of 150ppm glucose. 160ppm Class of water intended for primary contact recreation such as bathing, swimming, skin diving, etc. Class B Component of CFC’s CFC ’s that causes destruction of 100,000 molecules of ozone. chlorine Denitrification is carried out when bacteria break down nitrates and release nitrogen gas. What are these bacteria. Anaerobic bacteria. Anaerobic bacteria.
During which of the ff operating conditions of an automobile CO content in the exhaust gas is maximum idle running. Ecological Solid Waste Management Act of 2000 is otherwise known as RA as RA 9003 For a given temperature profiles, determine which profile is neutrally
stable.1 stable.1 From question no. 15, estimate the ground level conc. At 2km downwind, 0.1 km off the centerline. 60microgram/m3 Gas responsible for the rotten egg of waste water. Hydrogen Hydrogen sulfide. Generic term used to describe the particulate matter carried in the effluent gases from furnaces burning fossil fuels fly ash. Hardness of water is usually expressed as parts per million of CaCO3. If the three-day BOD (BOD 3 ) of a raw sewage is 55ppm (k=0.55/day), what is the ultimate BOD. 68ppm Insufficient washing of sand grains in a rapid sand filter causes mud balls. Involves the accumulation of trace metals through each species of the food chain. Biomagnification. chain. Biomagnification. It is a phenomenon that results in the overabundance in the algae growth in bodies of water. It is also the natural process of nutrient enrichment that occurs over time in a body of water. Eutrophication. water. Eutrophication. It is a very unstable gas used for disinfection, a very powerful oxidant capable of oxidizing 200 to 300 times more than chlorine and can reduce complex taste, odor and color ozone. It is defined as the controlled decomposition of organic materials, such as leaves, grass, and food scraps. composting It is defined as the role of the organisms in the community. Niche. It is described as the c loud of air pollution trapped by thermal inversion. smog It is used a s bonding agents in building and furniture construction which may cause drowsiness, nausea and headaches when exposed to low level concentration. formaldehyde concentration. formaldehyde Legislation that presents the revised water usage and classification. DENR AO no. 34. Maximum allowable concentration of CO 2 in air for safe working is 5000 ppm. 5000 ppm. Most aquatic organisms can survive in pH range of about 6 to 9. Most commonly used coagulating agent. Aluminum agent. Aluminum sulfate. Nitrates more than 50ppm in water leads to a disease called mathenoglobenemia. Organisms that belong to the second trophic level. Herbivores. level. Herbivores. PAN is a powerful lachrymator or t ear producer formed from unburned hydrocarbons, aldehydes, nitrogen oxides and oxygen. PAN stands for peroxyacetyl nitrate. Part of the atmosphere where most of the photochemical reactions take place. Mesosphere. place. Mesosphere. Particulates (< 1micrometer) remaining suspended in air indefinitely and transported by wind currents are called aerosols Problem Solving Process of converting nitrogen gas to ammonia is called nitrogen fixation. Process where decomposers return back the nitrogen to the soils t hrough the remains and waste of plants and animals. Ammonification. animals. Ammonification.
Process whereby coarse matter (suspended or floating) of a certain size can be strained out of flowing water with the aid of bars, fine wires or rocks. Screening. Recyclable material labeled as no. 3 PVC. 3 PVC. Removal of all settleable particles rendered settleable under the influence of gravity, basically the theory of gravity under the influence of which all particles heavier than water tend to settle down. Sedimentation. Temporary hardness is hardness is a substance in water is removed by Lime Soda Process. The alkalinity of wastewater is due to the presence of the following except dissolved CO2. The amount of chlorine available in water a fter the disinfection is called residual chlorine. The liquid produced when water percolates through any permeable material. leachate The permissible color for domestic water supply in ppm is 20. The pH of a water sample was found to be 6.3. The bicarbonate was measured to be 2.1x10 -3 M. Calculate the total carbonate if pK a1 a1 and pk a2 a2 are 3.3 and 10.33, respectively. 2.8x10-3 The process of killing infective bacteria in water is called sterilization. called sterilization. The process where more harmful substances are produced from less harmful ones. Synergism. The red brownish color of water is due to the presence of dissolved impurities of iron and manganese. The resistance of water to the passage of light through it is a measure of the turbidity. The total solids in water are due to the presence of suspended and dissolved solids. These are accumulated solids removed from separation equipment such as settling tanks and clarifiers. sludge. clarifiers. sludge. These are closed compartments that use gravitational force to extract dust and mist and typically used only for larger particles. Settling chamber These organisms feed on the waste of the ecosystem. Detritivores. ecosystem. Detritivores. These reddish brown oxides in concentrated form may produce an abnormal accumulation of fluids in the lungs. NO lungs. NO x This provides the blueprint for action t owards sustainable development Agenda 21 Total uptake of chemicals by an organism from food items as well as via mass transport of dissolved chemicals. Bioaccumulation. chemicals. Bioaccumulation. Type of recycling that involves recovery of chemicals or energy from post-consumer waste materials. tertiary Type of wastewater treatment that employs biological methods to remove fine suspended, colloidal and diss olved organics by biochemical oxidation. Secondary treatment. Type of wastewater treatment that employs physical and chemical treatment methods to remove or reduce a high percentage of suspend solids and toxic materials. Primary materials. Primary treatment. Water treatment that destroys disease-causing bacteria, nuisance bacteria, parasites and other organisms and remove soluble iron, manganese and hydrogen sulfide from water. Chlorination. What is the atmospheric condition when the lapse rate is >10 OC/km. Superadiabatic. When a sample of water is added to a medium of agar and incubated at 37OC for 24hours, colonies of bacteria formed are countered. This test is called Total Count Test. Which of the ff is NOT classified as heavy industry in the list of environmentally critical projects.. Forestry projects.. Forestry projects
Which of the following is NOT a physical characteristic of wastewater. Hardness. Which of the following is not use for the disinfection of water. Sulfuric acid. Which of the following is not used as adsorbent material. Water. Which of the following maybe used to measure the assimilative capacit y of a stream. BOD. stream. BOD.
4 kg of water is placed in an enclosed volume of 1m3 heated until 150C. Mass vapor is 2.542 kg.
A heat pump provides 75MJ/hr to a house. Compressors require 4kW of energy. COP is 5.21
A steel cast ing 40kg at 450C is quenched in 150kg oil. Entropy is 9.8kJ/kg.
Air undergoes isentropic compression from 14.7 psia, 68F to 180.6psia and 621.5F. -94.8Btu/lbm An ice-making machine operates cyclica lly between 0-25C. The work done to freeze 100kg water at 0C to ice is 733.94kcal. An ideal Otto engine operating at the end of compression (840F) and expansion (2540F) with compression ratio of 7.5. Efficiency is 55.3% An Otto cycle compression ratio of 7.5 operates at 14.2psia and 85F. The pressure and temperature at the end are 238psia, 759F.
Calculate the entropy of steam at 60psia with a quality 0.6. 1.16
The work polytropic compression pf air from 15psia, 1ft3 to 150 psia and 0.15 ft3 is 5150ft-lb. 5150ft-lb. The work required to compress a gas reversibly according to pV 1.3 is 50000ft-lb. Change in internal energy is 48.2Btu The work required to compress a gas reversibly according to pV 1.3 is 50000ft-lb. Heat loss is -16.1 Btu There are removed 500Btu/min of heat from 440R to 550R. if COP is ¾ of Carnot, heat rejected is 667Btu/min.
From 80F and 6ft3, 10lb H2 changes to 150F and 10ft3. Entropy is 8.1Btu/R From above find volume of vapor 0.9985m3. From above, heat rejected is 13.3Btu. From above, work done is 27Btu. From above, work done is -719btu/lb air From above, work input is 3.95hp.
How many TOR required to produce 10MT of ice at -10C to 22C i f losses are 15% of the chilling and freezing load. 17TOR If 150 L of N2 gas expands adiabatically at 1 atm to final volume of 250 L. 0.49 atm In a Carnot cycle operating on N2, heat supplied is 40Btu and expansion ratio is 15.6 at 60F. Efficiency is 67%. In an isentropic compression, P1- 100 psia, P2- 200 psia, V1- 10in3 and y1.4. Find V2V2 - 6.1in3
Steam engine is operating at 220-35C and delivers 8hp and efficiency of 30%. What is the actual efficiency. 11.3% Steam generated in a power plant at 8600kPa and 500C fed to a turbine. Exhaust at 10kPa is saturated liquid. The efficiency of Rankine cycle is 39.7%. Steam is expanded from 700F and 200psia to 5psia in an 87% efficient turbine. Final enthalpy is 1105.23 Btu/lbm
If 1lbm of steam at 14.7psia, 63% quality is heated isentropically, at what pressure. 2585 psia
experiment that 1.000 gram of M combines with an excess oxygen to form 2.019 grams of oxide. The element M is manganese
27 13
4
Al 2 He
mass Fe3O4 = 23g, In the reaction of Fe 3O4 with carbon to form carbon dioxide and iron, the number of moles of carbon required to convert Fe3O4 to product 0.2. mass fraction solute = 35 ppm . What is the concentration of chloride ion in percent in a solution that contains chloride 3.5 E-3%. mass mixture (Cu2O and CuO) = 1.000g mass Cu = 0.865. The mass of Cu2O in the original sample of the mixture must have been 0.742g. mass O2 = 10.0g . What is the theoretical yield of SO 2 for the reaction of the given mass O 2 with sufficient S for complete reaction. 20.0g.
30
P X
15
9 1 Be 1 H 4 Be
___
2 1 H
8
Be
% composition HC C = 84.2% H = 15.8% . What is its empirical formula C 4 H. 54.45% carbon 9.09% hydrogen, 36.36% oxygen . What is the empirical formula. C 2 H 4O. a 1-L vessel established equilibrium with the following reaction: 2SO 2 + O2 = 2SO3 mol SO2 = 0.11 0.11 mol O2 = 0.05 mol SO3 = 0.12 another 1-L vessel is used and contains SO 2 mass SO2 = 96g . How much O 2 (in grams) must be added, if at equilibrium, one half of SO2 will be converted to SO 3 13.34.
a compound containing only phosphorus and hydrogen was fully combusted mass yield P 4O10 = 17.9g mass yield H 2O = 4.80g. What is the empirical formula of the compound PH 2. 2.
GENERAL CHEMISTRY
mass compound sample with C,H,O = 0.95g , when fully combusted in oxygen gives mass H 2O = 0.518g . mass CO 2 = 2.13g . What is the simplest or empirical formula. C 5 H 6 6 O2.
Naturally occurring Ga is composed of 60% Ga-69 Ga-69 and 40% Ga-71 atomic mass Ga-69 = 68.911 atomic mass Ga-71 = 70.931. Calculate the average atomic mass of Ga 69.72amu. roasting of 100g of copper ore yields 75.4g of 89.5% pure copper . If the ore is composed of Cu 2S and CuS with 11% inert impurity, calculate the percentage of Cu2S in the ore . 62%.
wt % sand = 70, wt % water = 30 density pure quartz = 165 lb/ft 3 . What is the density of the mud, the sand is practically pure quartz 110.4 lb/ft 3,
[HBr] = 0.1 V HBr = 50 m l [KOH] titrant = 0.1M V base = 49mL. Calculate the pH after the volume of base has been added to 50 ml of HBr 3.0 [HCl] = 0.0015M . What is the concentration of OH in water solution 6.7E12M [HCl] = 0.10M volume HCl = 50.0ml [NaOH] = 0.20M, volume NaOH = 100ml . What is the pH of the resulting solution 13 [HCN] = 0.100M Ka HCN = 7.2E-10 . What is the pH of a solution 5.1 [HF solution] = 0.1M % dissociation = 9.5%. Calculate the K a for HF 1.0E-3. [hydronium ion] = 2E-3M . What is the pH the a solution 2.7 [Mg2+] = 0.001M Ksp Mg(OH) 2 = 1.2E-11 . Calculate the pH of a solution necessary to just begin the precipitation of Mg(OH) 2 10 [NaOH] = 0.100M V NaOH = 180 ml [HAcetic] = 0.100, V acetic = 200 ml K a acetic acid = 1.8E-5 . What is the pH of a buffer prepared by adding NaOH to acetic acid 5.70 [NH3] = 0.0500M 0.0500M Kb NH3 = 1.8E-5 . What is the pH of a solution 11.0 [NH4Cl] = 0.256M [NH 3] = 1.8E-5 . What is the pH of NH 4Cl 4.92 A metal reacts with water with the evolution of hydrogen and formation of its hydroxide. mass metal = 1 g atom (the chloride of metal was found to contain 13.7% chlorine) volume OH solution = 1L [HCl]= 0.9091N volume HCl = 110ml. The volume of hydrogen gas liberated at STP 11.2. The atomic weight of the metal 224. Since the solution of the OH of the metal is normal, the valency of the metal is 1. buffer pH= 4.0 Ka benzoic acid = 6.5E-5. Which of the following following solutions results in a the given buffer 0.16M benzoate and 0.25M benzoic acid. C(s) + CO 2 = CO(g) Kc = 1.6, equilibrium concentration of CO 2 = 0.5M . What is the equilibrium concentration of CO. 0.89 H2 + I2 = HI Kc for HI equilibrium@425C = 54.5, [H 2]0 = 0.00623M [I2]0 = 0.00414M [HI] 0 = 0.0224M . Calculate the concentration of I 2 in equilibrium 0.00267M.
Ka HCN = 7.2E-10 . What is the ratio of acid concentration to anion concentration needed to produce a buffer of pH 10.0 using HCN and NaCN. 0.14 mass acid = 1.243g volume = 31.72 cm3 of 0.1923N. What is the equivalent weight of an acid of standard base for neutralization. 204 mass CaCO3 = 1.0kg . The maximum number of kilograms of CaO produced on heating 0.56kg. mass impure sample Na2CO3 = 1.2048g (is dissolved and allowed to react with a CaCl2 solution) mass of resulting precipitate CaCO 3 = 1.0362g . Assuming that the impurities do not contribute to the weight of the precipitate, calculate the percent purity of the Na2CO3. C% mass of impure ammonium aluminum sulfate = 759.08mg, the aluminum in the sample was precipitated as Al(OH) 3 and ignited at 1100C to yield Al 2O3mass Al2O3 = 387.953mg . Express the result of analysis in terms of %Al 27%. mass of KHP = 1.431g necessary in standardizing a solution of NaOH, mass alkali = 25.5ml mass acidrun back = = 8.25ml (1ml=10.75 NaOH). What is the molarity of the NaOH solution 0.2598. mass sample (containing Al(NO 3)3, AlCl3, and inert) = 1.7483g (divided into two equal portions) Case 1: portion [AgNO 3]titrant = 0.1M V AgNO 3 = 50mL excess was titrated back with 28.89ml of 0.1002 M KSCN for titration Case 2: portion 2, [NaOH] titrant = 0.1193M V NaOH = 26.02 ml to completely precipitate as Al(OH) 3 . Calculate the % AlCl 3 in the sample 10.70%. mass sample (Na2CO3, NaHCO3, inert) = 1.179g, titrated acid= 0.1N, HCl volume acid = 24ml, indicator = phenolphthalein . Another duplicate sample was titrated with HCl; using methyl red as indicator. It required 50.25ml of the acid for color change. What is the % NaHCO 3 in the sample. 18.7. mass sample = 253.02mg containing NaBr and KBr was dissolved in water and treated with AgNO 3 mass precipitate = 429.85mg. Calculate the %NBr in a sample 49%. mass sample crude ammonium salt = 1.00g (treated with hot KOH solution) [acid] = 0.5N V acid= 50mL [NaOH] = 0.2N, 3.12 mL for neutralization . Calculate the %NH3 in the sample 41.25% mass sample mixture (NaOH, Na 2CO3, inert impurity) = 1.2g [HCl] titer = 0.5M indicator = phenolphthalein phenolphthalein . the solution turns colorless colorless after the addition of 30ml of the acid as a required for the color change to pink. Methyl orange is then added and 5ml more of the acid are needed to color change. What is the % Na 2CO3 in the sample. 22.08 mass sample of impure AlCl 3 = 1.500g was dissolved in water and treated with AgNO3 using Mohr method [AgNO 3]titrant = 0.1000M V AgNO 3 = 45.32ml . Determine its purity AlCl 3 (133.33 g/mol) 13.43%. mass vinegar = 3g titrated acid = 0.115N KOH, volume acid = 20.50ml indicator = phenolphthalein. What is the percentage of the total acid expressed as acetic acid in a sample of vinegar for an end point with the given indicator 6.72%. mole AgCN = 0.0010 volume = 1L K HCN = 4E-10, Ksp AgCN AgCN = 1.6E14 . What (H +) is needed to dissolve completely AgCN 0.025M n ammonia = 0.25 mol K b b = 1.8E-5 . What is the pH of a solution prepared from ammonia dissolved in sufficient water to make 1L solution 11.33. pH buffer = 5 . What is the ratio of the concentration of acetic acid to sodium acetate 0.56 solubility barium sulphate = 0.0091g/L @ 25C MW barium sulphate = 233g/mol . What is the solubility product constant of barium sulphate. 1.523E-9. sp.gr HCl solution (23.81%wt. HCl)= 1.12. How many grams of HCl are present in each milliliter solution. 0.27 volume of 0.1N NaOH= 10ml volume of 0.1N HAc= 25ml Calculate the pH of the solution 4.57. What are the percentages by mass of each element in CaCl 2. 36.1%Ca and 63.9% Cl.
mass alkane = 2.2g mass bromine = 3.2g . The molecular formula of A C 8 H 16, 16, moles alkane = I mole, moles water = 7 moles . an alkane reacts with excess O2 to give water. The alkane could be hexane. moles alkane = I mole, moles water = 7 moles . moles of CO2 generated from the same alkane 6. saponification number of triglyceride = 200 . Average MW of triglyceride 840.
Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide. NH4(s)↔ (s)↔ NH3(g) + HI(g) K p p @ 400C = 0.215. If 150g of ammonium iodide is placed into a 3-L vessel and heated to 400C, calculate the partial pressure of ammonia when equilibrium is reached. 0.46 atm. angstrom = 3.92 face-centered cubic crystal density = 21.5 g/ml . What is its atomic weight 195. At volume vessel 1 = 1L established equilibrium with the rxn: 2SO 2 + O2 = 2 SO3 mol SO2 = 0.11 mol O2 = 0.05 mol SO 3 = 0.12 @volume vessel 2 = 1L mass SO2 = 96g initially. How much O 2 (in grams) must be added, if at equilibrium, one half of SO 2 will be converted to SO 3 13.34. Calculate the root mean square speed of a helium atom at 298K 1363 m/s charge = 8.5E3coulombs . How many grams of iron (Fe) could be deposited from a solution of FeCl 2 2.46. D tube = 3mm Length tube = 78.74 inches, Pressure head = 6.5 N/cm 2, volume fluid = 0.04 m 3 passes through the tube every 1 minute. What is the viscosity of the fluid. 0.097cP. E = 75,000 cal/mol (pyrolysis of ethane). How much faster is the decomposition at 650C than at 500C. 2795 times faster. electrical current = 10 amperes . What is the mass of aluminum produced in 1 hour in the electrolysis of molten aluminum sulfate 3.36g. t1/2 of radioactive isotope C-14 = 5720 years mass of sample carbon = 1.00g 1.00g undergoes 15 disintegrations per minute per gram. How old is a 10.0g sample for which the rate i s 0.91 disintegrations per minute per gram 4120 years. frequency: 5.11E+11 Hz . What is the wavelength of radiation 5.87E-4 m. heat of combustion methanol = -173.7 kcal/mol @18C, heat of combustion CO = -67.6 kcal/mol @ 18Cn heat of formation of H 2O(l) = -68.4 kcl/mol . Find the heat of reaction at 18C for CO(g) + 2H 2(g) = CH 3OH(l) -30.7 kcal. mass calcium nitrate = 11.3g mass water = 115g . What is the freezing point of a solution -3.34C mass defect for the triton (tritium nucleus) = 0.00910amu. Calculate the binding energy per nucleon 2.825 MeV. mass Fe(s) = 1.67g t = 1.00 hour . What current would be necessary to deposit Fe(s) from a solution of Fe3+ (aq) 2.40A. mass gas density bulb evacuated/empty = 29.3215g 29.3215g mass bulb with CO2 gas @40C, 1 atm = 30.0079g mass bulb with CO and CO 2 at same T&P = 29.9332g . Determine the % of CO in the mixture 29.9. mass hydrogen= 0.504g time the current is liberated= 2 hours. How many grams of copper can be liberated by t he same current flowing for the same time in a copper sulfate solution. 15.9. mass isotope = 1 g t 1/2 isotope = 15 hours . The half-life of 0.50g sample 15 hours. mass isotope = 1g t 1/2 = 15 hours . The half life of 0.50g sample 7.5 hours. mass metal = 400g heated to =96.5C mass H 2O at calorimeter = 2000g @20C Tf = = 21.5C . What is the specific heat of the metal in cal/g.C 0.10 mass N2O4 = 1.588g total pressure = 1.0133 bar, volume glass vessel @ 25C = 500 cm 3 . What is the value of Kp. 0.143 bar.
mass of flask evacuated = 134.567g pressure gas = 735torr @ 310C, mass of flask after filling with gas @ given P and T = 137.456g mass of flask filled with water@31C = 1067.9g . Assuming ideal gas equation applies, calculate the molar mass of the unknown gas 79.7. mole Cl2 = 1.00 mol V = 1.00L T = 200K, a=0.493L 2-atm/mol2 b=0.5622 L/mol . What is the pressure calculated by van der waals equation 31.0 atm. moles of electrons = 3.00 potential = 1.74 V, What is the electrical work done 5.07E5J. PCl3(g) PCl3(g) + Cl2(g), dissociates, T = 250C P = 1 atm heat
density = 4.4g/L at equilibrium . The fraction of PCl 5 dissociated is 0.103. T = 25C . The difference between the heat of combustion of methane at constant pressure and at constant volume when liquid water forms -1257.4 cal. T = 27C . The difference between the heat of combustion of methane at constant pressure and at constant volume at the given temperature when the liquid water forms. -1192.2 cal. T1 = 20C T2 = 100C electric current = 10A, voltage = 10V t = 10 hours. Calculate the mass of water in grams that could be heated 10,755. viscosity coeff of gaseous Cl = 147.0 micropoise @ 20C. Find the molecular diameter of the chlorine molecule. 4.22E-8cm. volume 1 methane= 200ml Temperature= -42C, volume 2 methane= 100ml . Find the final temperature 74. volume gas mixture (N 2 and CO 2) = 10.0 L (with 3.00g N 2), PT = 0.750atm\ T = 273K . What is the partial pressure of CO 2(g) in the mixture. 0.510 atm. VP pure benzene @ 25C = 0.1252 atm ma ss unknown HC= 6.4g mass, pure benzene (MW=78) = 78g VP benzene in solution = 0.1192 atm . What is the molar weight of the unknown solid. 128. VP pure ethyl alcohol @ 30C = 71.2 torr VP pure carbon tetrachloride = 121.6 torr mass ethyl alcohol = 20g mass carbon tetrachloride = 60g . Calculate the pressure above a solution assuming ideal behavior 95.0 torr. Z = 2.50 @ 65.0 atm n gas = 2.00 moles, V gas = 1.00L P = 65.0 atm. What is the temperature of this gas 158K.
a closed gaseous system system undergoes a reversible process Qrejected = 25 BTU V1 = 5ft 3 V2 = 2ft 3 P = (constant) 50psia. Find delta U 2.76 BTU. heat content of 70% NaOH liquor @ 160F = 325 btu/lb is diluted with 20% NaOH liquor @ 80F heat content 20% NaOH liquor = 40 btu/lb heat content final solution, 40% NaOH = 94 btu/lb . For every 100lb product, how much heat must be removed to maintain a final product temperature of 100F. 6000 btu. heat engine absorbs heat from the combustion of gasoline @ T=2200C, sp.gr of gasoline = 0.8 heat combustion = 11,200 calories per gram T = 1200C, engine rejects heat . The maximum work in calories that can be obtained from the combustion of 1L gasoline 3.26E6 cal. heat of combustion benzoic acid = -770.9 kcal/mol (measured in bomb calorimeter) @ 25C . Find the heat of combustion of benzoic acid in kcal/mol at 25C in a stream of oxygen assuming complete condensation of water vapor to liquid -771.2. helium is compressed isothermally P= 14.7 psia, T = 68 F compression ratio = 4 . Determine the change in entropy of the gas in BTU/lb-F 0.689. mass Cu = 5lb T = 200F mass water = 10lb m . Copper is submerged in water and after a period of time, equilibrium is established. What is the entropy change of the system. 0.0167 BTU/R. mass ice cubes = 5 lbs (manufacture from water initially at 32F) T, surrounding air = 80F latent heat of fusion of water = 143.4 btu/lb. The minimum work 70.0 btu.
mass of ice = 100g. T 1 = 0C (ice) T2 = 100 C @ 1 atm (steam) . Calculate the change in entropy in converting ice to steam 205.28eu. mass of oxygen gas = 8 grams @ 27C, 10 atm and expands adiabatically and reversibly P final = 1.0 atm . The work done done in the process - 752 J. moles of ideal gas= 3 @ P = 1 atm @ T = 20C, 20C, heated at constant pressure T final = 80C C v = 7.50 + 3.2E-2T, cal/mol.K. The change in internal energy of the process is 3210.50 cal. P1 = 1 bar (initial condition air is compressed) @ 25C, P 2 = 5 bars @ 25C . Assume air is ideal gas, calculate the work done in J/mol 3990. Calculate the heat required in J/mol -3990. P1 = 200kPa P 2 = 150 kPa . For an ideal gas, what is the specific molar entropy change during an isothermal process. 2.39 J/mol-K. Psat steam = 350 kPa mixed mixed with water at 15C 15C Thot water = = (produced from mixing) 80C rate mixing = 4 kg/s internal diameter = 50mm (inlet and outlet lines to the mi xing device) . At what rate must steam be supplied 0.41 kg/s. Q = 1055kJ T = 427C (heat engine absorbs heat), T = 38C (heat engine rejects heat) . The work done in kJ by the engine if its efficiency is 50% of the carnot engine is closest to 496.6kJ. Qabsorb = 1055kJ @ T =427C, T reject = 38C . The work done in kJ by the engine if its efficiency is 50% of the Carnot efficiency is closest to 293.3 kJ. refrigerator capacity = 3140 watts input rating = 735 watts. The coefficient of performance of the refrigerator is 4.27. T = 100C (water evaporates) @ 1 at m . Calculate the work done by the system in which 1 kmole of water evaporated 3060 kJ. Tsteam = 212F mass water = 400lb, T water = = 70F heat losses = 2000 Btu . Find the amount of steam to make the T F of water to be 212F 60.6 lb. two carnot engines engines are operating operating in series. T1 (absorbs) = 1,111K T 2 (rejects), the second engine receives the heat at the intermediate temperature T and rejects it to Treservoir T reservoir = 300K . Calculate T if the efficiencies of the two engines are equal. 577K Required Required 2: From the data above, calculate T i f the work done by the two engines are equal. 705K. VP acetic acid @ 90C = 293 293 mmHg VP acetic acid @ 100C = 417 mmHg . Calculate the normal boiling point of acetic acid 391.3K.
A fixture containing an ordinary incandescent light bulb is connected to a dimmer switch. Temperature of the tungsten filament inside the bulb increases from 1300K- 2600K. 2600K. Total Power radiated by the bulb. Increase 16x A heat exchanger is required to c ool 20kg/s of water. T= 360K to 340K. m=25kg/s. Tentering water = 300K. Overall coefficient of heat transfer= 2 kW/m2-K.Calculate the surface area required in a counter concentric tube exchanger. 20m2 A method where engineers assure the existence of an exchanger and make calculations to determine if the exchanger would handle the process. Rate process. Rate an exchanger A popular type of heat exchanger for cooling large quantities of fluid. Low thermal conductivity A reaction mixture,Cp= 2.85 kJ/kg-K, flowing at a rate= 7260kg/hr. to be cooled from 377.6K to 344.3K. Tcooling water= 288.8K, flow rate= 4536kg/hr. OHTC= 653 W/m 2-K.Calculate the outlet water temperature. 51.95°C A single 4-in steel pipe, OD = 4.5 inch, outer surface temperature= 300°F. The horizontal pipe in a large room with ambient temperature= 78°F at standard barometer. The heat total (natural convection and radiation) for 25ft of length in Btu/hr. 21100 Air Tin=75°C, Tout= 225°F. Hot gas: T out= 265°F. LMTD= 140°F. Find the temperature of the hot gas entering. 325°F An economizer receives hot gas (Cp=0.27 BTU/lb-°R) and water in the ratio of 1.5 lb gas per lb water. Tgas in= 850°C. Tgas out= 355°F. Twater in= 120°F. Find the exit temperature of the water if the flow is parallel. 320°F An insulator should have. Low have. Low thermal conductivity conductivity Benzene at 100°F and 1 atm flows at 100ft3/min in a smooth 1” ID tube. The heat transfer coefficient for the system in BTU/ sec-ft2-°F Calculate the inside area of the coil in ft2. 2.664 4. Calculate the gpm of water cooled. 0.380 Composite wall at 2000°F. Outside ambient temperature at 70°F. Three layers composite wall, 12, 12 and 10 inches. Thermal conductivities: 0.4,0.2 and 0.1BTU/hr-ft-°F. Inside heat transfer is negligible. Outside air film heat transfer coefficient is 2BTU/hr-ft2-°F. Heat loss through the composite wall in BTU/hr-ft 2 is. 118.2 Composite wall composed of 2” cork on the inside, 6” concrete and 3” wool on the outside. Thermal conductivities= 0.025,0.8 and 0.065 BTU/ hr-ft-°F. Inside surface temperature= 40°F. outside t emp=78°F. What is the heat flux through the wall in BTU/hr-ft 2. 3.41
Determine the rate of conduction of copper rod. Diameter= 2mm, Length= 150 mm. Temperatures: 300°C at one end and 20°C at the other end. Ave. thermal conductivity= 1.36E6 J/s-m-K. 7890W Determine the temperature (in °F) at the junction between the firebrick and the insulating brick. 1533 brick. 1533 Determine the temperature (in °F) at the junction between the insulating brick and common brick. 328 6.Calculate 328 6.Calculate the heat loss per linear foot from 2in nominal pipe (2.375 in outside diam eter). Covered with 1 inch of an insulating material. average thermal conductivity= 0.0375 BTU/hr-ft-°F. Temperatures of the insulation= 390°F and 80°F. 120BTU/hr-ft Dittus-Boelter equation for the determination of heat transfer coeff. is valid. For valid. For fluids in turbulent flow Film and drop are the terms associated with. Condensation Find the thermal conductivity of a 0.5m thick material with an area of 5m2 and a temperature difference of 10K if the heat transmitted during 2hrs of test is 2000kJ. 2.78 W/m-K Flat wall with 6inch layer firebrick( k=0.95BTU/ hr-ft-°F), 4inches insulating brick (k=0.14), and 4inches common brick (k=0.8). Firewall temperature= 1800°F, outer surface temperature= 120°F. The heat loss through the wall in BTU/hr-ft 2. 506 Heat loss (W/m2) by radiation & convection from an unlagged horizontal steam pipe, 50mm, od. At 377K. Air at 283K. 1587 Heat transfer area for a natural convection. Horizontal pipe diameter= 0.15m. Surface temperature of 400K to air at 294K. 6.81 W/m2-K Convection coefficient of heat transfer of nickel wire(0.035 in diameter at 1700°F) to air is equal t o 6 BTU/ hr-ft 2-°F. How much heat is lost by 1ft of wire inside an oxidized copper container, the air and container being 160°F. 85BTU/hr Hollow metal sphere. Inside wall temperature= 300°F. Internal diameter= 6 inches and 2inch thick. Outer surface= 212°F. Thermal conductivity of metal= 8BTU/hr-ft-°F. What is the heat loss from the sphere. 5529BTU/hr Hollow sphere. Outside radius= 1m made up of polystyrene foam. Thickness= 1cm. the inner surface is 5.20°C hotter than the outside surface. Thermal conductivity of polystyrene foam= 0.033 W/m-°C. The power produced by the heat source. 214 W How much part of the light is absorbed by the body that t ransmits and reflects 80% and 10% respectively. 10% If a man touches two metals which were kept together at room temperature, why would one metal feel colder than the other. One other. One has higher thermal conductivity In a heat transfer equipment, dirt or scale may be accounted by introducing a resistance called. Fouling called. Fouling factors In a steady state heat t ransfer through a series of materials with varying resistance, the heat transfer. Is constant throughout the series of materials In convection heat transfer, the mechanism of heat transfer where the fluid moves due to the decrease in its density caused by increased in temperature. Natural temperature. Natural convection In heat exchanger the area of heat transfer is calculated from. The from. The total lateral area of the tubes LMTD. 230°F Metal rod= 10cm long, diameter= 2cm. One end is in contact with steam at 100°C while the other end is in contact with ice at 0°C. 320g of ice melted after 20 mins. The thermal conductivity is. 283.6 W/m-K Methyl alcohol flowing in the inner pipe of a double pipe exchanger is cooled with water flowing in the jacket. Inner pipe= 1-inch(25mm), Sched 40 steel pipe. Steel thermal conductivity= 26 BTU/hr-ft-°F(45 W/m- °C). hi = 180 BTU/hr-ft 2-°F(1020 W/m 2-°C), hdi= 1000 BTU/ hrft2-°F (5680 W/m 2-°C), ho= 600 BTU/ hr-ft 2-°F(3402 W/m 2-°C), hdo= 500 BTU/hr-ft 2-°F(2840 W/m 2-°C). What is the overall heat transfer coefficient based on the outside area of the inner pipe in BTU/hr-ft 2-°F). 80.9
Pipe diameter= 50mm with circular section with walls 3mm thick covered with two concentric layers of lagging. Inner layer thickness= 25mm with thermal conductivity= 0.08 W/m-K. outer layer thickness= 40mm with thermal conductivity= 0.04 W/m-K. What is the rate of heat per meter length of pipe. Ti= 550K, T o surface temp= 330K. 62.7W/m 330K. 62.7W/m Ratio of the molecular diffusivity and momentum in liquid is known as the. Prandtl the. Prandtl no. no. Refractory material… Emissivity of 0.40 at 1500K and 0.43 at1420K. Temperature of 1420K exposed to black furnace walls at 1500K. The rate of gain of heat by radiation per unit area in Kw/m 2. 24.3 Stack gases leave a boiler, pa ss through a square steel duct 3ft by 3ft and 16ft long. And enter a masonry chimney. Estimate the heat transfer coefficient (in BTU/hr-ft2-°F) in the duct if the gases are at 900°F and 1 atm. Consider the stack gases to have the same properties as air. The gas velocity is 50ft/sec. Steam pipe. Outside diameter= 2inches. Inside surface temperature= 350°F. pipe coating material= 2inch thick. Thermal conductivity: k= 0.5 + 5E-4T in °F. k in BTU/hr-ft-°F. Outside surface coating= 100°F. Calculate the heat loss per foot of pipe length. 877 BTU/hr Surface temperature is. 129.1°F The area assuming it’s co-current. co -current. 6.46m2 The area assuming it’s counter current. 5.43m2 The inside and outside surfaces of window glass are 20°C and -5°C. Glass: 100cm by 50cm in size and 1.5cm thick. Thermal conductivity= 0.78 W/m-K. Heat loss through the glass at 2hrs. 1.30kWh The main trunk duct of an air conditioning system is rectangular in cross-section(16in x 30in) and has air at 15psia and 40°F flowing through it with velocity of 1400 fpm. Find hi in BTU/ hr-ft 2-°F. 4.50 The mode of heat transfer that can take place in a vacuum. Radiation The overall conductance for a composite material in series is equal to the. Inverse the. Inverse of the total resistance The total heat loss by radiation and convection from unlagged horizontal steram pipe of 50mm diameter at 415K at air= 290K. 384W/m The transfer of heat through and by means of matter. Conduction The view factor F21 of a sphere(1) of diameter D inside a cubical box(2) of length L which is equal to D is. 0.524 Two very large walls at constant temperatures (800°F and 1000°F). Emissivities: 0.6 & 0.8. Net exchange heat in BTU/hr-ft 2. 1825 Water cooler uses 50lb/hr of melting ice to cool running water from 80°F to 42°F. Ui= 110 BTU/hr-ft 2-°F. Find the LMTD. 24.24 °F What is the reason why Styrofoam is a good insulating material. Because it contains many tiny air pockets of air
2000kg/h of a mixture consisting of 60%wt benzene and 40%wt toluene is to be separated in a distillation column. The distillate is to contain 98%wt benzene and 95% of the feed benzene is to be recovered as distillate. what is the flow rate of the distillate. 1163kg/h 41.78o Be is equivalent to 42.12 oAPI. A contract was made between a buyer and a paper manufacturer for paper containing 5% moisture at P450/ton on specification that price adjustment will be made if the quality is different. How much should the buyer pay for 1 ton of paper with 8% moisture content. Freight cost is P45/ton. P434.16 P45/ton. P434.16 A dehumidifier sprays 50lb/min of cold water into a stream of air. 100lb/min of wet air enters the dehumidifying chamber. The absolute humidity of the entering air is 0.05lbwater/lb d.a. What is the total of the liquid water leaving the chamber per minute. 53.81 A mixing tank mixes two inlet streams containing salt. The salt concentration in stream 1 is 5% by weight and in stream 2 15% by
weight. S1 flows at 25kg/s while S2 at 10kg/s. there is only one exit stream. Find the salt concentration in the exit. 8% A solution of gravity of 100 o Twadell. Calculate the specific gravity in degrees Baume. 48.33 A typical mud is 70 wt% sand and 30% wt water. What is its density. The sand is practically pure quartz (SiO 2) for which its density is 165 lb/ft3. 110.4lb/ft 3 Ethylene reacts with water to form ethyl alcohol. If 20g of each reactant is used, 20g of alcohol is produced. What is the percent yield. 60.9% Fresh orange juice contains 12%wt solids. Initially a single evaporation process was used for the concentration to 45%wt but volatile constituents of the juice escaped with water, leaving the concentration with a flat taste. The present process overcomes this problem by bypassing the evaporator with a fraction of the fresh juice; the juice juice that enters the evaporator is concentrated to 58% solids and the product is mixed with the bypassed fresh juice to achieve the desired final concentration of solids. Calculate the fraction of t he feed that bypassed the evaporator. 10% From data above, calculate the %benzene in the bottom. 7.2% From the data above, calculate the flow rate of the bottom product. 837kg/h H2 gas can be prepared by the reacti on of zinc metal with HCl solution according to the equation: Zn + 2HCl ZnCl2 + H 2 How many liters of H2 gas will be formed at 762mmHg and 15 oC if 25.5g Zn was allowed to react with HCl. 9.44L How many pounds/day of CaF 2 is needed t o produce 3000lb of a 60% HF acid/day if the yield is 90% and the rock contains 95% pure CaF 2. 4105.2 One dried will dry a material from 45% (wb) to 20% (db). From here, the material enters another drier where the water content is further reduced to give a final product weighing 1000kg. if the total evaporated water from both driers is 800 kg, the moisture content (wb) of the final product is 1%. Pig iron is prepared in a blast furnace from a hematite ore. The ore contains 83% ferric oxide. The pig iron produced is 96% Fe and the Fe in the ore slag contains 10% of t he iron in the ore. How much pig iron is produced for every 500tons of ore. 272 tons The CO2 that will theoretically be formed when a mixture of 50g of methane and 100g oxygen is ignited is 68.8g. The equivalent of 45 oTw in the Baume scale is 26.63 The waste acid from a nitration plant operation contains 23% HNO 2, 57% H2SO4 and 20%H2O. It is specified that the concentrated acid product contains 27%HNO2, 60% H 2SO4 and 13% water. If the H 2SO4 available contains 7%H2O and the HNO 2 contains 10% water, how many lbs of the waste acid is needed to produce 1000lb of the product. 418.3lb
A fuel containing 75% ethane and 25% propane is burned with dry air. All the H2 burns to water and CO 2 to CO ratio is 10:1. 15% excess air is supplied. Calculate a) mole stack gas/ 100 mole fuel; b) Orsat analysis of stack gas; c) complete analysis of stack gas; d) m3 dry air at 28C and 765mmhg per mole fuel. a. 2294.75 moles, b. %CO= 1.038% %CO2=10.38%, O2=3.47%, N 2= 85.11%, c. – c. – , d. 0.521m3 /mol A fuel containing methane and ethane is burned with excess air. The analysis of the dry stack gas is given as follows: 4.62%CO2, 3.08%CO, 8.91%O2 and 83.39%N 2. Determine the %excess air. 49.81% A furnace is fired with petroleum containing 80%C, 13%H, 3%S, 1%N and 3%O. Determine the moles of theo air required for the complete combustion of 1kg of oil. 472
A pure saturated hydrocarbon is burned with excess air. The analysis of the product of combustion shows 9.08%CO 2, 1.63%CO, 5.28%O 2 and no free H 2. Determine the hydrocarbon C 3 H 8. A pure saturated hydrocarbon is burnt with excess air. Orsat analysis of the stack gas shows 7.9% CO 2, 1.18%CO, 0.24% H 2 and 85.43% N 2. Air is substantially dry. The stack gases leaves at 750mmHg. Dry air required for the burning of 1ft 3 of CO is 2.4ft 3. From the data above, determine the mole percent of ethane in the fuel. 18.57% If the test study on the combustion of the cetane-methyl naphthalene mixture gave a product analysing 7.14% CO 2 4.28% CO 8.24%O 2 and the rest N2, what is the cetane number of the diesel. Density of cetane is 0.775g/ml and n-heptane is 0.684g/ml. 44.71 The analysis of flue gas from a fuel gas is containing no nitrogen is 4.62%CO2, 3.08%CO, 8.91% O 2 and 83.39% N 2. Calculate the %excess air if all the fuel is burned. 50
100 lb of sodium carbonate in water at 10C to 30C. 185lb 100lb Sodium sulphate at 40C cooled to 5C. 69.5lb 13% K 2Cr 2O7 from 1000 lb soln cooled to 20C with 640 evaporated water. 103.6lb A solution of NaNO 3 in water at 40C contains 49% NaNO3 by weight. 92% Ammonium chloride at 70C cooled to crystallize 45% of the solution. 9.5% From above %yield is 95%. From above, % yield is 10.8%. From above, concentration of NaNO 3 per 100g water. 81.8g From above, molality of the solution is 9.64m. 9.64m. From above, molarity of the solution is 7M. From above, percent yield. 80% From above, weight sodium nitrate cooled to 0C. 4.84g From problem above, weight NaNO 3 from 1000lbs by reducing temperature to 10C. 82 Percent yield of the process above. 16.8% Sodium nitrate at 60C contains 45% sodium nitrate. % saturation is 66%.
1000lb pile of mixture of 20% sand and 80%KCl. Drained solids a fter 1st leach is 1206lb. Drained solids after 2nd leach is 253.9 solids. %KCl= 27% or 21%. 21%. Collective drained solids is 2806lbs. %KCl from collective= 28.37%. A solvent extraction will will be performed on a solid B that contains a soluble component A (Xa= 0.25 Xb=0.75). Lb solute A/lb A&B to obtain 95% A is 1.67%. How many stages and how much water is needed for the countercurrent extraction of NaOH of feed of 80lb NaOH,400lb water and 100lbCaCO3. 580lb, 3.14~4stages. Roasted copper ore with 10%CuSO 4 85% gangue and 5% moisture. Percent CuSO4 underflow 0.13%. 0.13%. %Recovery is 97.96%.
a cooling coil, consisting of a single length of tubing through which water is circulated, is provided in a reaction vessel, the contents of which are ket uniformly at 360K by means of a stirrer. T inlet cooling water = 280K, Toutlet cooling water = 320K. What would be the outlet water temperature if the length of the cooling coil were increased by 5 times. Assume the overall heat transfer coefficient to be constant over the length of the tube and independent of the water temperature. 357.5K a shell-and-tube heat exchanger consists of 120 tubes of internal diameter 22mm and length 2.5m. It is operated as a single pass condenser with benzene condensing at 350K on the outside of the t ubes and water of inlet temperature 290K passing through the tubes. Initially there is no scale on the walls, rate of condensation = 4 kg/s, water velocity = 0.7m/s, scale resisitance = 0.0002m 2-K/W (formed on the inner surface of the tubes), latent heat of vaporization benzene = 400kJ/kg. To what value must the water velocity be increased in order to maintain the same rate of condensation on assumption that the transfer coefficient on the water side is proportional to the velocity raised to the 0.8 power, and that the coefficient for the condensing vapor is 2.52 kW/m2-K, based on the inside area. 2.06m/s a shell-and-tube heat exchanger is used for preheating the feed to an evaporator. liquid specific heat = 4.0kJ/kg-K, density liquid = 1100 kg/m3, Tsteam condensing = 395K on the outside The exchanger heats liquid at 295K to an outlet temperature of 375K when the flowrate is 1.75x10-4
m3/s and to 370K when the flowrate is 3.25x10E-4 m 3/s. What is the heat transfer area and the value of the overall coefficient when the flow rate is 1.75x10-4 m 3/s. 0.136kW/m2; 9.09m2 a thermometer is immersed in a liquid which is heated at the rate of 0.05K/s, Uto the bulb = 735 u 0.8 W/m 2-K, area of the bulb = 0.01m 2. If the thermometer and the liquid are both initially at 290K, what rate of passage of liquid over over the bulb of the thermometer thermometer is required required if the error in the thermometer reading after 600s is to be no more than 1 deg K. Take the water equivalent of the thermometer as 30g. 0.82 m/s benzene is to be condensed in a vertical shell and tube type of heat exchanger fitted with tubes of 25mm outside diameter and 2.5 long, rate = 1.25kg/s, *vapor condenses on the outside of the tubes, T cooling water enter = 295K, rate cooling water = 1.05 m/s, tube wall thickness = 1.6mm. Calculate the number of tubes required if the heat exchanger is arranged for single pass of the cooling water. 60 tubes are required Calculate the time for the distant face to reach 470K under the same conditions as, except that the distant face is not perfectly lagged but a very large thickness of material of the same thermal properties as the brickwork i s stacked against it. t=2.26x10E5 s or 0.226 Ms (62.8h; t=2.38x10E5s or 0.238 Ms (66.1h) co-current flow cooler, T 1 oil = 370K, T 2 oil = 350K, *temperature is reduced by lengthening the cooler, T water enter = 285K, T oil enter = 420K, Twater leaving = 310K (original cooler), *the oil and water flowrates, inlet temperatures and other dimensions of the cooler will remain constant. If the original length is 1m, what must be the new length. 1.86m countercurrent-flow heat exchanger, benzene is cooled using water, mass flow rate benzene = 1.25kg/s, density benzene = 880 kg/m 3, specific heat benzene = 1.9 kJ/kg-K, T 1 = 350K, T 2 = 300K, T water = = 290K, external diameter heat exchanger = 25mm, internal diameter heat exchanger = 22mm, *water passes through the tubes, film coefficient water = 0.85kW/m2-K, film coefficient benzene = 1.70 kW/m2-K, *scale resistance is neglected. What total length of tube will be required if the minimum quantity of water is to be used and its temperature is not to be allowed to rise above 320K. 165.8m Density HC = 950 kg/m 3; Specific heat capacity = 2.5 kJ/kg.K; T 1 HC = 363 K; T 2HC = 313 K; T 1 water = 293 K; T 2 water = 323 K; flowrate HC = 0.56 kg/s HC is cooled in heat exchanger with water countercurrently. What is the required flowrate of water. G=0.56 kg/s. After plant modifications, the heat exchanger is incorrectly connected so that the two streams are in co-current flow. What are the new outlet temperatures of HC and water, if the overall heat transfer coefficient is unchanged. 324.2 K; 315.8K depth longitudinal fin = 75mm, thickness fin = 3mm, T pipe surface = 400K, coefficient of heat transfer surface 5W/m2(constant), thermal surface = conductivity fin = 50W/m-K, T base of t he fin = 400K. Calculate the heat dissipated per meter length from the fin to the atmosphere at 290K, the heat loss from the extreme edge of the fin may be neglected. 6.23 W/m diameter cast-iron vessel = 1m, diameter propeller agitator = 0.3m, frequency propeller = 2 Hz, mass flow rate circulat ing cooling water = 0.5 kg/s, outside diameter steel coil = 25mm, inside diameter steel coil = 22mm, diameter helix = 0.81 m, mean water temperature = 290K *the conditions are such that the reacting material may be considered to have the same physical properties as 75% sulphuric acid/ What is the overall heat transfer coefficient. 458.7 W/m2-K diameter one end of metal bar = 25mm, length bar = 0.3 m, T bar = 375K, *heat is dissipated from the whole length of the bar to surroundings at 295K, coefficient of heat transfer from the surface = 10 W/m 2, thermal conductivity metal = 85 W/m-K. What is the rate of loss of heat. 12.5 W Diameter open bowl = 0.3 mm; T=350K (evaporating water into the atmosphere); mass water = 10 kg. If the air currents are sufficiently strong to remove the water vapor as it is formed and if the resistance to its mass transfer in air is equivalent to that of a 1mm layer for
conditions of molecular diffusion, what will be the rate of cooling due to evaporation. 0.026 deg K/s diameter open cylindrical tank = 500mm,depth tank = 1 m (three quarters filled with a liquid),liquid density = 980 kg/m 3, specific heat capacity = 3 kJ/kg-k, overall heat transfer coefficient for the coil = 100 W/m2-K, Tsurrounding = 288K. If the heat transfer coefficient from the cylindrical walls and the base of the tank is 10 W/m 2-K and from the surface is 20 W/m 2-K, what area of heating coil, fed with steam at 383K, is required to heat the contents from 288K to 368K in half hour. 5.0m2 dimension rectangular ingot = 15cm x 15cm x 30cm, T initial of ingot = 290K, T = 1400K (silica brick), emissivitytotal =0.78 (oxidized iron surface), density of iron = 7.2 mg/m 3, specific heat capacity of iron = 0.50 kJ/kgK. How long will it take to heat the ingot to 600K, it may be assumed that the furnace is large compared with the ingot, and that the ingot is always at uniform temperature throughout its volume. convection effects are negligible. 200s distance between two large parallel plates (gray body) = 75mm, emissivity 1 = 0.8 @ 350K, emissivity 2 = 0.4 @ 300K. Calculate the net rate of heat exchange by radiation per square meter taking the StefanBoltzmann constant as 5.67x10E-8 W/m 2-K. 143.7 W/m 2 emissivity of refractory material = 0.40 @ 1500K, emissivity of refractory material = 0.43 @ 1420K, T = 1500K (black furnace wall). What is the rate of gain of heat by radiation per unit area.. 24.3kW/m2 flow rate gas = 2.5 kg/m 2-s, Re = 20, 000, specific heat of gas @ constant pressure = 1.67 kJ/kg-K. What will be the heat transfer coefficient be. h=13.4 W/m2-K heat is transferred from one fluid to a second fluid across a heat transfer surface. film coefficients for two fluids = 1.0 and 1.5kW/m 2-K, thickness metal = 6mm, thermal conductivity metal = 20 W/m-K, scale coefficient = 850 W/m 2-K. What is the overall heat transfer coefficient.. 317.5W/m2 K or 0.318 kW/m2-K in a shell-and-tube type of heat exchanger with horizontal tubes 25mm external diameter and 22mm internal diameter, benzene is condensed on the outside of the tubes by means of water flowing through the tubes, rate = 0.03m 3/s, Twater enter = 290K, T water leaves = 300K, heat transfer coefficient = 850W/m2-K. What total length of tubing will be required. 526m internal diameter smooth tube in a condenser = 25mm, length tube = 10 m, pressure drop over the length of the tube = 2x10E4 N/m 2, coefficient for the condensing vapor = 15,000 W/m 2-K, latent heat of vaporization = 800 kJ/kg. If vapor at a temperature of 353K is condensing on the outside of the tube and the temperature of the cooling water rises from 293K at inlet to 333K at outlet, what is the value of the overall heat transfer coefficient based on the inside area of the tube. what is the film coefficient for the water. what is the rate of condensation of vapor. U=6.57 kW/m2; hi=11.68 kW/m2-K;0.235 kg/s internal diameter spherical insulated vessel = 2m, *vessels are well lagged on the outside, thermal conductivity = 0.07 W/m-K, latent heat of vaporization of oxygen = 215kJ/kg, boiling point oxygen = 90K, density pf liquid oxygen = 1140 kg/m 3, atmospheric temperature=288K, heat transfer coefficient from the outside surface of the lagging surface to atmosphere = 4.5 W/m 2-K.. What thickness of magnesia la gging must be used so that no more more than 1% of the liquid oxygen oxygen evaporates during a journey of 10ks (2.78h) if the vessel is initially 80% full. 0.25m internal diameter steam pipe = 150mm, T steam = 444K *lagged with 50mm of 85% magnesia. What will be the heat loss to the air at 294K. 132 W/m; 90% by the addition of 50mm of lagging liquid is heated in a vessel by means of steam which is supplied to an internal coil in the vessel, mass of liquid in the vessel = 1000kg, *it takes half an hour to heat the contents from 293 to 368K if the coil is supplies with steam at 373K. the process is modified so that the liquid at 293K is continuously fed to the vessel at the rate of 0.28 kg/s. the total contents of the vessel are always being maintained at 1000kg. What is the
equilibrium temperature which the contents of the vessel will reach, if heat losses to the surroundings are neglected and the overall heat transfer coefficient remains constant. T=360.7K mass flow rate air = 0.9kg/s , T 1 = 283K, T 2 = 366K, T flue gas entering = 700K, Tflue gas leaving = 366K, free flow mass velocity flue gas = 10 kg/m 2s, inner and outer diameter pipe = 12mm, specific heat capacity of air and flue gases = 1.0 kJ/kg-K, *air passing through the pipes of a bank consisting of 20 rows with 20 pipes in each row. the arrangement is in-line with center to center spacing, in both directions, equal to twice the pipe diameter. Neglecting gas radiation, how long should the pipes be. Values of k and which may be used for both air and flue gases, are given below. 1.73m mass flow rate crude oil = 37.5 kg/s, T 1 = 295K, T 2 = 330K, mass flow rate bottom product = 29.6 kg/s, T 1 = 420K, T2 = 380K, shell diameter = 0.60m (tubular exchanger), having one pass on the shell side and two passes on the tube side., number of tubes = 324, outside diameter = 19mm, wall = 2.1mm, length = 3.65m, square pitch = 25mm *supported by baffles with a 25% cut, spaced at 230mm intervals. Would this exchanger be suitable. 0.234m2-K/kW mass of pure iso-butane = 7.5 kg/s , T = 331.7K (condensed temperature), Tinlet water = = 301K, outside diameter tube = 19mm, wall= 1.6mm, triangular pitch = 25mm, scale resistance = 0.0005m 2-K/W. Determine the number and arrangement of the tubes in the shell. 8.5% Order of reaction = 2 nd order; diffusivity of gas = 10E-8 m 2/s; rate of absorption at the interface = 4x10E-6 kmol/m2-s. In a continuous steady state reactor, a slightly soluble gas is absorbed into a liquid in which it dissolves and reacts, the gas concentration in the liquid falls to one half of its value in the liquid over a distance of 1mm, calculate the reaction rate constant on the assumption that the liquid is semi-finite in extent and that mass transfer resistance in the gas phase is negligible. 212 m3 /kmol-s Outside diameter pipe = 50mm; T steam = 413K; Coefficient of heat transfer (from its outer surface to the surroundings) = 10 W/m 2.K @ 288K. What is the heat loss per unit length. Q = 196W/m. It is desired to add lagging of thermal conductivity 0.03 W/m-K as a thick layer to the outside of the pipe in order to cut heat losses by 90%. If the heat transfer from the outside surface of the lagging is 5 W/m 2-K, what is the thickness of lagging. x=52.5mm lagging. x=52.5mm outside diameter unlagged horizontal pipe = 50mm. Calculate the total heat loss by radiation and convection from unlagged horizontal steam pipe at 415K to air at 290K. 163.7 W/m; 344.7 W/m outside temperature = 293K, thermal conductivity of lagging D = 0.05 W/m-K, coefficient for heat loss by radiation and convection from outside surface vessel = 10 W/m2-K, outside area of vessel = 8m, coil area = 0.2 m2, overall heat transfer coefficient for steam coil=300 W/m 2K. The contents of a reaction vessel are heated by means of steam at 393K supplied to a heating coil which is totally immersed in the liquid. When the vessel has a layer of lagging 50mm thick on its outer surfaces, it takes one hour to heat the liquid from 293 to 373K. How long will it take if the thickness of lagging is doubled. 3147s(0.87H) pipe diameter=50mm (covered with two concentric layers of lagging), thickness pipe wall = 3mm, inner layer thickness = 25mm, thermal conductivity inner layer = 0.08 W/m-K, outer layer thickness = 40mm, thermal conductivity outer layer = 0.04 W/m-K. What is the rate of heat loss per meter length of pipe if the temperature inside the pipe is 550K and the outside surface temperature is 330K. 62.7 W/m t = 100s; diffusivity of CO 2 in ethanol = 4x10E-9 m 2/s. A deep pool of ethanol is suddenly exposed to an atmosphere consisting of pure carbon dioxide and unsteady state mass transfer, governed by Fick’s law, what proportion of the absorbed carbon dioxide will have accumulated in 1mm thick layer of ethanol closest to the surface. 0.83 or 83% t =1800s (0.5h) to heat a tank of liquid using steam supplied to an immersed coil; T1 = 293K; T2 = 323K; Tsteam = 383K *the overall heat transfer coefficient from the steam coil to the tank is 10 times the
coefficient from the tank to surroundings at a temperature of 293K. How long will it take when the steam temperature is raised to 393K. 1578s (0.44h) T distillation column = 350K; P distillation column = 500 mmHg; mol A (more volatile) = 0.7 (at the interface with the liquid) = 0.5 (in the bulk of the vapor); vapor); diffusivity in the vapor mixture = 2x10E-5 m2/s *the molar latent heat of the more volatile component is 1.5 times that of the less volatile *the resistance to mass transfer in the vapor may be considered to lie in a stagnant film of thickness 0.5mm at the interface. R = 8314 J/kmol-K. Calculate the mass transfer rates kmol/m 2-s of the two components. X a = 0.598. Calculate the mol fractions and concentration gradients of the two components at the midpoint of the film. Assume that the ideal gas law is applicable. 9.16 kmol/m 4 T packed column = 295K; P = atmospheric ; [ammonia-air mixture] initial = 10%; [ammonia-air mixture] final = 0.1 % after scrubbing with water; partial pressure ammonia ammonia = 660 N/m N/m 2, at some intermediate point where the ammonia concentration is reduced to 5%; transfer rate = 10E-3 kmol/m2.s. If the whole of the resistance to mass transfer may be regarded as lying within a thin laminar film on the gas side of the gasliquid interface, derive from first principles an expression for the rate of absorption at any position in the column. 0.24 cm2 /s. What is the thickness of the hypothetical gas film if the diffusivity af ammonia in air is 0.24 cm 2/s. 0.043 mm T1 air = 289K; T 2 air = 313K *warming the air by passing it through a number of parallel metal tubes; inner diameter tubes = 50mm @ 373K; pressure drop = not not exceed 250 N/m2; density air @ 301K = 1.19 kg/m 3; k (convection) = 45, 62, 77 W/m 2-K; velocity @ 301K = 20,24,30 m/s. How long should the individual tubes be.. 1.95 the radiation received by the earth’s surface on a clear day with the sun overhead is 1kW/m 2 and an additional 0.3kW/m 2 , approximate radius earth = 700, 000km, distance between sun and earth = 150, 000, 000km. The temperature of the sun, the sun may be assumed to behave as black body. 5710K thermal conductivity brick=1.0 W/m-K, thickness brick = 230mm, thermal conductivity plaster = 0.4W/m-K, thickness plaster = 10mm. If a temperature difference of 30K is maintained between the two outer faces, what is the heat flow per unit area of wall. 129W thermal diffusivity, DH = 0.0042 cm 2/s, thickness ID = 0.45m, T initial =290K, T2 = 470K , if the near face is suddenly raised to a temperature of 870K and maintained at that temperature. Assume that all the heat flow is perpendicular to the faces of the wall and that the distant face is perfectly insulated, calculate the time taken for the distant face of a brick wall. t=0.120 Ms (33.5h) thickness firebrick furnace = 0.2m, T = 1573K (inside furnace wall), T =293K (ambient air adjacent to the furnace exterior), ho =3.0T E 0.25 W/m2-K (natural convection heat transfer coefficient at the exterior surface), thermal conductivity of firebrick = 1.5 W/m-K, thermal conductivity insulating brick = 0.4 W/m-K. The heat loss through a firebrick furnace wall is to be reduced by addition of a layer of insu lating brick to the outside. What is the thickness of insulating brick necessary to reduce the heat loss to 400 W/m 2. x=1.18m Tsteam reaction vessel = 393K, area of steam coil = 2.5 m 2, area external surface = 40 m 2. overall heat transfer coefficient from the coil to the liquid in the vessel = 400 W/m 2-K. It takes 1800s to heat the contents from 293 to 373K when the outside temperature is 293K. When the outside and initial temperatures are 278K, it takes 2700s to heat the contents to 373K, show that the overall coefficient for transfer from the vessel to the surroundings is about 5W/m 2-K. 5 W/m2-K Twater = 293K, length coil = 6.1m, internal diameter pipe = 25mm, thermal conductivity of the pipe wall = 20 W/m-K, wall thickness = 3.2mm, Tsteam = 373K, film coefficient = 8 kW/m 2-K, water velocity in pipe = 1 m/s, T outlet = 309K. What will the outlet temperature be if the velocity is increased to 1.3 m/s, if the coefficient of heat transfer to the
water in the tube is proportional to the velocity raised to the 0.8 power. K=976; T=307.7K Velocity air = 12.2 m/s; T air = 66 K; densit y air @ 310K = 1.14 kg/m3;; What will be the c orresponding pressure drop for a pipe temperature of 420K and an air temperature of 310K. 101.8 (N/m 2 )/m velocity air thru pipe = 12 m/s, inside diameter = 25mm, k (convection) = 60 W/m2-K. Neglecting the effects of temperature variation, estimate the pressure drop per meter length of pipe. 115.2 N/m 2 per meter velocity water = 1.2 m/s (through series of 25mm diameter tubes 5m long maintained at 320K), T inlet = 290K. At what temperature would it leave. 306.4K; 306.06K volume jacketed reaction vessel = 0.25 m3, density liquid inside vessel = 900 kg/m3, specific heat = 3.3 kJ/kg-K, *the contents of the tank are agitated by a stirrer rotating at 3 Hz, heat transfer area =2.5 m 2, Tsteam = 380K, outside film heat transfer coefficient = 1.7 kW/m 2, tank wall = 10mm, thermal conductivity tank wall = 6.0 W/m-K, inside film coefficient = 1.1kW/m2-K, for a stirrer speed of 1.5Hz and proportional to the two-thirds power of the speed of rotation. Neglecting heat losses and the heat capacity of the tank, how long will it take to raise the temperature of the liquid from 295 to 375K. 2381s (40min) volume liquid = 0.1 m 3. specific heat capacity = 3kJ/kg-K, density = 950 kg/m3, heat transfer area = 1m2, Tsteam supplied = 383K, overall heat transfer coefficient in coil = 2000 W/m 2-K, heat transfer coefficient to surroundings = 311.8K. How long will it take to heat the liquid from 293K to 368K, if the tank, of external area 20m 2 is losing heat to the surroundings at 293K. To what temperature will the system fall i n 1800s is the steam is turned off.. 1559 s(0.43h); 311.8K volume liquid = 0.18m 3, density liquid = 900kg/m 3, specific heat liquid = 2.1kJ/kg-K, T 1 = 293K, T 2 = 377K, Tsteam feed= 383K, overall heat transfer coefficient = (constant) 0.5 kW/m 2-K, external surface vessel = 2.5m, coefficient for heat transfer to the surroundings = 5W/m 2-K @ 293K, how long will it take to heat the liquid , 2085s (0.58h). The batch system of heating is to be replaced by a continuous countercurrent heat exchanger in which the heating medium is a liquid entering at 388K and leaving at 333K. If the heat transfer coefficient is 250W/m 2-K, what heat exchange area is required. Heat losses may be neglected. 2.44m2 x firebrick = 225mm, k=1.4 W/m-K, x insulating brick = 120mm, k=0.2 W/m-K, x building brick = 225mm, k=0.7 W/m-K, T inside = 1200K, Toutside = 330K. Find the heat loss per unit area and the temperature at the junction of the firebrick and insulating brick. 803.3 W/m2; 589K
Estimate the boiling point… 15-mol% 15 -mol% NaCl, 10-mol%MgCl2 and 18mol% CaCl2… 140o F For the same duty and heat transfer area, the feedforward flow evaporator is ___ compared to backward feed… less efficient If the OHTC of the evap. of prob 10 is 200 BTU/hr-ft2- oF… the heating area in ft 2 … 38 If the sol’n to be evaporated tends t o strongly scale… forced scale… forced circulation circulation In a country where capital is scarce and energy cost is low… single low… single effect evaporator In evaporation operation, the valuable product is… thick liquor Referring to prob 13, economy of evap… 0.80 Referring to prob 13, estimated heating surface in m 2… 0.70 Referring to prob. 21, heat transfer area of the 1 st? 66.1 Referring to prob. 21, heat transfer area of the 2 nd? 68.8 Sat. steam at 25psia enters a surface… the required cooling water in lb/hr? 4130 The BPR of 30%wt NaCl at 1 atm… 20o F The concentration of glycerine from water solution… solution … evaporation The temp. driving force in an evap. is determined as difference between condensing steam and… boiling point of the sol’n Water enters the bottom of a vertical evaporator tube 20ft long… fraction of the liquid water entering the bottom? 0.0217 When the pressure of the evaporator chamber is decreased, the boiling point inside will decrease Which of the two evaporator…needs fluid motive devices to transfer solutions… backward feed
A 10%wt NaOH sol’n at 80 oF… the heating surface required in ft2… 91 A 7wt% NaOH sol’n enters an evap. at 98 oF… the number of BTU required to evap. 1.5lb H 2O… 1670 BTU A certain evap. is boiling a solution… after 4hrs and 10min… coefficient at the start of operation… 652 operation… 652 A double effect evap. is heated w/ st eam at 250 oF. The 2 nd effect is under vacuum… Boiling Point in 1 st… 208o F A heat transfer device that is normally used to liquefy vapors… condenser A liquor containing 15% solids is concentrated to 55%. The feed rate is 2.5kg/s… evaporation in 1 st in kg/min? 52.5 A sol’n of organic colloids is concentrated from 20 to 65%... the steam consumption in kg/hr… 11,400 A triple effect evap. is supplied with 250 oF sat. steam… the area of the first effect in ft2… 3300
A P&FFP contains 24 frames, each 1 in thick … the capacity of the press is? 936 ft 3 /day A P&FFP is used to filter a certain sludge for 2hrs at constant pressure. Time of washing is? 96 mins A P&FFP is used to filt er a compressible sludge (s=0.45) at 50 psifor 2 hrs… the washing time is? 127 min A P&FFP with 10 frames is used to filter a slurry at a constant pressure… the time to produce 400lb of filtrate, assuming Rm=0 Rm=0 is? 7.5 min A rotary drum filter with 35% of its filtering area submerged in the slurry turns t urns at 0.5 rpm… estimated area of the filter cloth in m 2? 1.6 A rotary vacuum filter w/ negligible filter medium resistance delivers 125 ft 3 of filtrate per minute… the volume of filtrate delivered per hour is? 10,620 ft 3
A small leaf filter is run at constant rate… the filtrate collected in 20 minutes is? 41.5 gallons A standard leaf filter gives 20 ft 3 of filtrate in 2 hrs of filt ration time per cycle… the capacity of leaf filter in ft 3/hr is? 4.4 During filtration of slurry, the filtration will st art to fall once the pressure … becomes constant During filtration on a rotary filter, the precipitate is continuously removed by scrapper in order to … keep the filter clean For a non-washing constant pressure filtration where the resistance of the medium is negligible, max. capacity is attained when the filtration time is… equal If a duplicate pump were installed in parallel with the present pump in prob 15, the percent reduction reduction in filtration time is? 7.7%
A multiple contact extraction system is to treat 1.25 tons (2,500 lbs)/hr of dry black ash containing 40% Na 2CO3… the number of ideal stage req’d is? 2 stages a slurry of flaked soybeans weighing 100kg contains 75kg inert solids and 25k g solution… composition of underflow leaving the extraction? 0.8 A unit op. in which a soluble component is removed from an inert solid by solvent which dissolves the soluble soluble matter is known as… leaching Agitation in liquid influences the rate of extraction. Agitation of solvent is important because… it increases the transfer material …
Coconut oil is to be produced from dry copra in two stages… dry copra cake contains 20% residual oil… number of ideal stages required is? 5 stages Composition of salt in weight percent in the final underflow is? 0.89%
If only ½ of the original filtrate volume of prob 15 were to be collected, the new filtration is? 24.4 min In a constant rate filtration test, the pressure rises from 4 to 45 psi in 10 mins collecting 3 ft 3 of filtrate… the equivalent resistance in ft3 is? 0.293 In a Plate&Frame filter press, the rate of filtration is directly proportional to… cross section of the filter press In filtration operation, the flow rate is directly proportional to … pressure applied In filtration, the coarser the filtration medium… the longer In P&FFP, the rate of washing is equal to? ¼ In the filtration of Al(OH) 3, the following data were obtained: the pump is operated at 50 psia… the total filtration time is? 38.3 mins Referring to prob. 9, if the drum has diameter of 1.0m, the width in cm? 51 The capacity of a rotary vacuum filter will change by a factor of 1.1 if the submerged area is increased by 20%. The eq’n: V f 2=22.5x103(θf +0.11)… the total cycle time for maximum filtrate output during 24 hr is? 12 hrs
Extraction of coffee from its seed is done by… leaching In a salt recovery plant, rock salt is being leached to produce industrial salt… inerts=70%, soluble salts=25%, moisture=5%... quantity of salts recovered in MT/day is? 12.1 In ideal leaching conditions, the tie slant to the right indicating that the solute solute is more highly concentrated in the underflow because… equilibrium solubility/incomplete leaching In leaching, the particle size influences the extraction rate, the smaller the size… greater size… greater interfacial area and smaller smaller the distance (both a and b) Leaching Leaching of sugar from sugar beets is done using… hot water Number of extraction extraction cells req’d if each ton of dry dry pulp retains retains 3 tons of of water? 17 Powdered limestone (CaCO 3) containing 10,000ppm NaOH… the NaOH content of the washed and dried limestone in ppm is? 0.8 Raw gypsum from a fertilizer plant is being leached out of its salt (NaCl)… raw gypsum = 10MT/day, Salt content=1%wt, water feed rate=90m3/day… the % of the salt removed is? 99.9%
The equation that is applied to describe the flowof a fluid through a porous medium… Kozeny-Karman medium… Kozeny-Karman Eqn. Eqn.
Roasted copper ore containing the copper as CuSO 4 is to be extracted in a countercurrent stage extractor… 10 tons gangue, 1.2 tons CuSO 4, 0.5 tons of water… the number of stages req’d is? 10
The filter fabric (or filter medium) to use in which strong breaking tenacity and strong abrasion resistance are req’d is? Nylon is? Nylon
Stage efficiency in a leaching process depends on the… both a and b
The operation by which solids are separated from liquids due to difference in densities… sedimentation densities… sedimentation
A countercurrent multiple contact extraction system is to t reat 50 tons/hr of wet sliced sugar beets… water=0.48, pulp=0.40, sugar=0.12… number of extraction cells req’d if each ton of dry pulp retains 3 tons of sol’n? 16
Tea percolation employs? Leaching employs? Leaching The major problem in leaching is to promote diffusion of the solute out of the solidand into the liquid. The most effective way is? to use countercurrent operation The rate of leaching increases with increasing… temperature increasing… temperature The resulting salt content in the overflow in weight % is? 0.112
The temp. also affects the rate of extraction. In most cases, the solubility of the material which is being extracted will increase with temp. to? Both to? Both a and b There are two underflow-overflow leaching conditions namely ideal a nd non-ideal. Ideal leaching condition exist if? All if? All of these Tung meal containing 55% oil is to be extracted at a rate of 4,000 kg/hr using n-hexane… n-hexane… theoretical number of stages is? 4 stages Which of the following operations does not involve leaching? Removing leaching? Removing nicotine from water sol’n by kerosene
The topic of drying and driers is taken up as part of Unit Operations in ChE since… the quality of the solid product is affected by moisture The value of constant drying rate, R c, varies directly with the quantity… therefore, increasing the humidity… decreases the rate of drying This is the moisture in the solid that exerts the equilibrium vapor pressure of the liquid at the prevailing conditions… conditions… unbound moisture This type of drier is used for drying pasty materials such as wet filter cakes and lumpy soils… soils… tray drier Unbound moisture in granular and porous solid moves through the interstices of a solid by a mechanism involving… moisture diffusivity
A wet material having a critical moisture content of 15% (d.b.) and an equil. Moisture content of 3% (d.b.)… 4.9 hours Drum driers are used for drying… pastes
under normal operating conditions, when a solid material to be dried is placed i nside a batch dryer, the ma terial i s usually subjected… under constant drying conditions
Given a solid material containing 120% moisture on a dry basis, the equivalent moisture in % moisture is… 54.5%
Wet solids are to be dried from 40% to 10% in 5 hours under constant drying conditions… The time needed to dry 15% to 5% under same conditions… 1.6 hours
If there’s no heat transfer by radiation and conduction from adjoining surfaces, the temp. of the solid subjected… nearly equal to the wet bulb temp of drying medium
When a porous solid is subjected to constant drying conditions starting w/ bound moisture, the removal of moisture from the solid is initiated by pendular state followed by funicular state… false state… false
In the absence of radiation and heat conduction through the solid during the constant drying rate period… wet bulb temp. of the gas
when a solid material is being dried in a continuous tunnel drier under low temperature drying, the mechanism is considered to be… simultaneous mass and heat heat transfer
In the constant rate period, the rate of drying is established by… a balance of heat requirements… In the drying at the falling rate period, the rate at which moisture is removed from the solid material… decreases with time It is a unit operations which involves the mass transfer of soluble materials from the liquid phase to gaseous phase… desorption It is the rate of drying under constant drying conditions with air at 140 oF and absolute humidity of 0.03lb water/lb dry air… R=0.5 -e-60X lb H2O/hr-ft2… equilibrium moisture content of material… 0.01155 the choice of equipment to be used for drying of solids can be classi fied according… all of these
When a solid material is said to be “dry”, it means… the solid still contains very small amount of moisture when a wet granular solid material c ontained in a metal tray w/ insulated edges… the heat transfer mechanism involved in the drying opera tion is… by convection and radiation When a wet solid is brought in contact with air, the solids tends to lose moisture if the humidity in air is… is … lower than the humidity corresponding to the moisture cont. of the solid When drying a banana chips under the sun, the rate of drying is faster on a… a… hot and windy day When the solid is non porous… liquid diffusion
The critical moisture content of a solid depends on the drying history and the thickness of the material… true the equipment is operated immediately under unsteady state conditions… batch drying The estimated mass transfer coefficient for the above drying conditions is… 50lb H 2O/hr-ft 2- Δ H The first point of the falling rate period corresponds to… critical moisture drying the free moisture content of the solids does not depend upon … the nature by which heat is supplied The portion of water in the wet solid that cannot removed by the air in direct contact with the solid is called… equilibrium moisture content
A 25 mm ID wetted wall column is used to absorb dilute SO 2 in air at 293 K with a velocity of 2.2 m/s. i f D v= 0.455 ft 2/hr, the gas film coeff… 0.0373 A wetted wall column is usually preffered over a packed column to determine mass transfer coefficient experimentally because for a wetted wall column The mass transfer area Assuming that the penetration theory applies in an interfacial mass transfer contact, the liquid phase mass transfer coeff will increase by a factor…. 2 Co- current gas- liquid up flow contacting device is highly characterized by dispense bubble flow regime
Flooding condition is the only consideration that dictates the minimum column diameter that can be used for a specified gas absorption in a packed column False column False For an absorber (mass transfer from gas gas to liquid) the operating line always lies above the equilibrium solubility curve For moderately soluble gas with relatively little interaction between the gas and liquid molecules, the law which applies most to establish equilibrium relationship is Henry’s is Henry’s Law Given the individual mass transfer coeff and equilibrium eqn at 25 0C , k xa=60, k ya=15 mol/hr. ft 3mole fraction and x *=0.3226y…. 8.45 if the solute free gas flow rate is 500 kg-mole/hr of 0.10 mole ratio of solute entering the plate absorber at 1 atm, what is the minimum water.. 103 In a gas absorption column, the pressure of the lean gas is expected to be lower than In a gas absorption packed tower, the most economical gas velocity is considered to be about half In a gas absorption tower, mass transfer occurs primarily from the gas phase to the liquid phase In a stripping or desorption operation, the equilibrium curve is above the operating line In an absorption tower packings are placed inside to provide a bigger mass transfer area In gas absorption, packings are used to increase the area of contact between the gas and the liquid In gas absorption, the use of a liquid rate far above the minimum value will result in fewer number of plates In gas absorption, when the conditions at the bottom of the tower are fixed and the gas flow rate is given, the limit ing flow rate based on equil conditions that will require infinitely tall tower is maximum liquid flow rate In mass transfer, a transfer unit means that the concentration range is equal to the average driving force In packed columns, the pressure drop for irrigated packings is always greater than the pressure drop for dry packings because the flow area of dry packing is greater In the case of a straight or concave downward operating line and a straight or concave upward equilibrium line, the minimum li quid rate is that at which the operating line just touches the equil line at the bottom of the tower In the choice of a solvent for gas absorption, one of the properties to be considered is solvent is solvent should have a low low vapour pressure It has been determined that the equivalent HTU and NTU of a packed absorption tower are 0.85 ft and 15 respectively. If the same …. 1.275 It is a unit operation which involves the mass transfer of soluble materials from the solid phase to the liquid phase leaching It is not very necessary to correct the rate eqn for the phase drift encountered during gas absorption, since the height calculated will be slightly over designed anyway Pressure drop is one of the most important parameters in the design of two phase concurrent bed because all of these The analogy between mass and heat transfer is complete when no convective flus or phase drift is involved The interfacial concentration yl in a gas absorber corresponding to y= 0.05 mole fraction is _ mole fraction. The slope of the operating line is 1.3.. 0.02 The mass transfer rate of a material from one phase to another across an interface is increased by increasing The mechanism of mass transfer in a gas absorber is best described by the Two-Film Theory The method of separating a particular gaseous component from a mixture of gases due to their differences i n solubility I a liquid phase is absorption
The mole fraction of solute entering a gas absorber is 0.25. if the percentage recovery is 75% , then the mole fraction of the solute leaving…. 0.0769 The overall height of a transfer unit based on the gas phase will equal the gas phase individual HTU, H y when the liquid phase resistance is very small compared with the gas phase The pressure drop along a packed tower is directly proportional to the square of the mass flow rate The rate eqn in terms of the gas phase mass transfer coefficient is used in design calculations instead of that in terms of the liquid phase when the controlling resistance is that of the gas phase The total weight of a 13 mm ceramic raschig rings that can be contained in a cylindrical gas absorption tower 5m high and 0.55m in diamete r …. 1045 When dilute sol’ns are involved in gas absorption, one of thw following is not applicable =
When the gas flow rate induces flooding in a packed column gas absorber, this is best remedied…. increasing the diameter of the column When the liquid flow rate is fixed and the composition of the liquid and gas at the bottom of the absorption tower are fixed, t he limiting flow rate to give ifinitely tall tower becomes the minimum flow rate of the vapor When the two film theory is applied to gas absorption, the overall resistance can be expressed in terms…. the slope of the equil curve near the tie line is linear
A sling psychrometer is whirled on a fast spin when measuring the wet bulb temperature of ambient air to minimize the effect of radiation on the temperature reading Air conditioning involves dehumidification Air supplied at the rate of 1200 cfm to a refrigerated coil, has a relat ive humidity of 20% and dry bulb temp of 150 0F. The mass flow rate of dry air entering per minute is 74.1 An air-carbon tertrachloride-vapor mixture at 100 0F dry bulb and 60 0F wet bulb is heated until the temperature reaches 180 0F. The final percentage relative humidity is about 5% An indication of the moisture content of ambient air is its wet bulb temperature Besides measuring the dry bulb and wet bulb temperature in determining the humidity of air, another method may be used. This is by measuring the dew point of the air Fogging is a result of a condition whereby the gas becomes supersaturated with vapor For a cooling tower with a circulating water flow of 5000 gpm, an inlet and outlet water temperature of 100 0F and 80 0F, respectively and 0.5% drift loss, the estimated make-up water is 110 gpm For a dehumidifier, the slope of the tie line is 2.5 for a liquid to gas ratio of 1.0. air enters the dehumidifier at 80 0F db and 78 0F wb while water leaves at 760F. Estimate the interfacial temperature at a point …. 63.50 F For air-benzene vapor mixture at 1 atm, the dry bulb temperature is 1000F and wet bulb temperature of 90 0F. the absolute humidity at this condition is 0.52 For an air flow rate of 5000 lb/hr and a water flow rate of 7500 lb/hr, the temperature of the cold water is 80 0F using air with temperature of 90 0F dry bulb and 70 0F wet bulb. The estimated…. 880 F For dehumidification, when the top liquid flow rate is fixed and the top conditions of water temperature and air enthalpy.. maximum air flow rate For the air-water vapor system, the Lewis relation h y/k yc3 takes a value of essentially equal to unity Given a counter flow induced-draft cooling tower with the following operating data: hot water temperature= 115 0F, cooling range= 30 0F, wet
bulb temperature= 70 0F, water flow rate= 500 gal/min. Assuming…. 7 hp If 100 lb of dry air at 50 0F db and 50 0F wb is mixed with 300 lb of dry air at 1100F db and 80 0F wb, the resulting mixture will have a dry bulb.. 95 0 F If the air flow rate is 1000 lb/hr, the maximum water rate needed for the tower in the previous problem i s about 3400 lb/hr If the mass transfer coefficient, K Ga= 230 lbs water/hr-ft 3-atm, then the MTC in lb water/hr-ft 3-absolute humidity is 370.6 If the partial pressure of the vapour in a gas- vapour mixture is, for any reason, less than the equil vapor pressure of the liquid at the same temperature, the mixture is unsaturated If the temperature of t he air entering the t ower of the previous problem (problem 24) is 100 0F, the exit temperature of the air is estimated to be (use Mickley’s graphical method) 1050 F In adiabatic humidification, it is possible t o maintain the temperature of water constant since the system can be well insulated from the surroundings In an air water contact equipment, the individual gas phase mass transfer coefficient is equal to the over-all mass transfer coefficient since the mass transfer resistance in the liquid phase is small In an air-water contact operation, when the temperature and humidity of the air both decrease the process is dehumidification In dehumidification, where the Lewis number is equal to one, the operating line on the gas-enthalpy-liquid temperature graph is above the equilibrium curve In order for the gas to be dehumidified, as in the water vapor air mixture, the humidity of the gas must be greater than the gas-liquid interface In terms of heat transfer, the use of a cooling tower is said to be more efficient and more economical compared to an ordinary heat exchanger since temperature profiles of air and water can cross each other Moist air is found to contain 8.1 grams of water vapor per cubic foot at a temperature of 30 0C. Calculate the temp to which it must be heated…57 heated…57 0C The air in the room is at 26.7 0C and a pressure of 101.32 kPa and contains water vapor with a partial pressure Pa=2.76kPa. calculate the %.... 78.3% The dew point of air indicates the temperature at which its water content will start to condense The enthalpy entering and leaving a cooling tower is 52.0 and 75 BTU/lb, respectively. If the inlet and outlet water temperature are 1200F and 100 0F, respectively, respectively, the estimated overall…. 0.76 The enthalpy transfer eqn based on Merkel’s procedure of determining the volume of a cooling tower is a convenient way of eliminating the determination of interfacial temperature and humidity The enthalpy transfer equation as proposed by Merkel is applicable to air-water system only because the ratio of h e convective heat transfer coefficient and the mass transfer coefficient, k yMB is equal to the humid heat The height to diameter ratio of a cooling tower is much less compared to that of a gas absorber because the gas flow rate is larger The process which illustrates the principles of adiabatic humidification is spray is spray chamber The ratio between partial pressure of water vapour in air and the vapor pressure of the water at the air temperature multiplied by 100 is percentage relative humidity The relative humidity of air at a given temperature is the the ratio of the partial pressure of the water-vapor and the vapor pressure of water The relative humidity of unsaturated air-water vapor mixture is always greater than The temperature at which the moisture in humid air exerts a partial pressure equal to its vapor pressure pressure is called the dew point
The tons refrigeration needed to supply air in a room 20 ft by 20 ft by 10 ft charged every 5 min at 70 0F dry bulb and 65 0F wet bulb by cooling outside air at 120 0F db and 100 0wb is 14.3 The wet bulb temperature of the resulting mixture for the mixed air for the previous problem is 750 F This is a steady-state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapor-gas mixture wetbulb temperature This is the temperature at which a vapour gas mixture becomes saturated when cooled at constant humidity. dew point temperature This is the temperature of a vapour-gas mixture as ordinarily determined by immersion of a thermometer in the mixture dry bulb temperature Which of the following processes is followed by unsaturated air (with dry bulb temperature 12 0C and relative humidity 47%) passing through water spray washer (temp of water being constant at 40 0C). both heating and humid Without adding or removing any water vapor, a sample of air experiencing an increase in temperature will have lower relative humidity
1200 lb of barium nitrate is dissolved in sufficient water to form a saturated solution at 900C. Assuming that 5% of the weight of the original solution is lost through evaporation, calculate the crop of crystals obtained.. 962.4lbs A batch of 1000 kg of KCl is dissolved in sufficient water to make a saturated solution at 363K, where the solubility is 35% wt \k\cl in water. The solution is cooled to 293K at which temperature the solubility is 25.4% wt… 400g wt… 400g A diluent is added to the mixture, the solution is then directly or indirectly cooled and/or solvent is evaporated to effect crystallization solution crystallization A plant produces 30,000 MT of anhydrous sodium sulphate annually by crystallizing process sulphate brine at 0 0C. Yields of 95% and 90% in the crystallization and calcination operations are obtained,…. 2387 A solution of magnesium sulphate containing 43g solids per 100g watter is to be fed to a vacuum crystallizes at 220 0F. The vacuum in the crystallizer corresponds to a water boiling temperature of 43 0C… 5235 lbs per hour A solution of MgSO 4 at 2200F containing 43g of MgSO 4 per 100 g H 2O is fed to a cooling crystallizer operating at 50 0F. If the solution.. 3.71 tons/h A Swenson-Walker crystallizer is fed with a saturated solution of magnesium sulphate at 110 0F. The solution and its crystalline crop are cooled to 40 0F. The inlet solution contains 1 g of seed crystals per 100g of solution. The seeds are 80-mesh. Assuming ideal growth, the mesh size of the ..28 ..28 A Swenson-Walker crystallizer is to be used to produce 1 ton/hr of copperas crystals by cooling a saturated solution which enters the crystallizer at 1200F. The slurry leaving the crystallizer will be at 800C.. Compounds whose solubility increase with increasing temperature results in absorption of heat when the compound dissolves Cooling water required is.. 52 gpm Crystals of Na 2CO3-10H2O are dropped into a saturated solution of Na2CO3 in water at 1000C. What percent of the Na 2CO3 in the Na 2CO3H2O is recovered in the precipitated solid? The precipitated solid is…. 25% During crystallization, formation of crystal can occur in __ solution only supersaturated Equilibrium in crystallization process is reached when the solution is saturated Glaubers salt is made by crystallization from a water solution at 20 0C. The aqueous solution at 20 0C contains 8.4% sodium sulfate. How many
grams is 1.077 so that when the residue solution after evaporation is cooled at 20 degrees Celsius… 801.52 How much CaCl 26H2O must be dissolve in 100 kg of water at 20 0C to form a saturated solution? The solubility of CaCl 2 at 200C is 6.7 gmol anhydrous salt (CaCl 2) per kg of water 535 kg If an aqueous solution of 25% wt MgSO 4 at 140 0F is cooled to 30 0F, the mother liquor concentration will be _ %wt MgSO 4 18 In industrial crystallization from a solution, the two phase mixture of mother liquor and crystals of all sizes, which occupies the crystallizer and is withdrawn as product is called magma Most modern crystallizers fall in the category of__ units in which adiabatic evaporative cooling is used to create supersaturation Vacuum One ton of Na 2S2O3-5H2O is to be crystallized per hour by cooling a solution containing 56.5% sodium thiosulfate to 30 0C in a SwensonWalker crystallizer. Evaporation is negligible. The product is to be sized….1138.5 sized….1138.5 Referring to (previous problem), the type of crystals formed is MgSO42H 2O The concentration difference between that of the supersaturated solution in which the crystal is growing and that of a solution in equilibrium with the crystal is called supersaturation called supersaturation The enthalpy of a 25% wt of MgSO 4 at 82.2 0C in BTU/lb solution is 40 The enthalpy of MgSO 4-7H2O at 26.67 0C in BTU/lb solution is -150 is -150 The enthalpy of saturated MgSO 4 at 1500F in BTU/lb solution is -25 The equation relating the solubility of the substance to its particle size is called Kelvin called Kelvin The formation of a new solid phase either on an inert particle in the solution or in the solution itself is called nucleation The heat of solution of hydroxybenzene in g-cal/gmol is -2,605 The heat of solution of saltpeter in kg-cal/gmol is -8.633 The latent heat evolved when solid forms from solution which varies with both temperature and concentration is called heat of crystallization The number of crystallizer units to be used is.. 7 The solubility of Epsom Salt in equilibrium with the saturated solution at 100C in g/100g water is 30.90 The solubility of sal ammoniac at 70 0C in g/100g water is 60.2 The solubility of soda ash at 30 0C in g/100g water is 38.3 The solubility of sodium bicarbonate in water is 9.6g/100g of water at 20 0C and 16.4g/100g of water at 60 0C. If a saturated solution of NaHCO 3 at 600C is cooled to 20 0C, the percentage of the dissolved salt that crystallizes. 41.5% This crystallizer uses the method of supersaturation by evaporation of solvent Oslo Which of the following solute may be crystallized by cooling without evaporation, evaporation without cooling or a combination of cooling and evaporation Sodium Nitrate
80g of F 2 is reacted with 40g P 4 to form 90 g of product PF 3. A flue gas from a certain furnace burning a fuel of negligible nitrogen content is found by analysis to contain 12% CO 2, 7.5% O 2, and 80.5% N2. Calculate the percent excess air. 54.6% A mixture of acetone vapor and nitrogen contains 14.8% acetone by volume. Calculate the relative saturation and the % saturation of the mixture at a temperature of 20 C and pressure of 745 mmHg. 59.7%, 52.9% A sample of lignite was found to contain 34.55% moisture, 22.93% FC, 7.2% ash, 1.2% S, and 0.57% N with a calorific value of 16.45 MJ/kg. Calculate percent net H. 0.52% Calculate the percentage conversion. 92% Determine the percentage yield. 79% Hydrogen in fuel that needs oxygen from air for it s combustion is known as. Net as. Net Hydrogen
In the combustion of solid fuels, what is the key component between the feed and the refuse? Ash refuse? Ash In ultimate analysis, calculate percent H. 5.46% In ultimate analysis, calculate percent O. 39.52% It is normally used to det ermine the quality of combustion gases. Orsat Analysis It is the portion of t he coal which when heated in the absence of air under prescribed conditions is liberated as gases or or vapour. Volatile matter Pig iron is produced in a blast furnace from hematite ore containing 80% Fe2O3. The pig iron produced is 96% Fe. The slag contains 10% of iron present in the ore. How many tons of pig iron is produced per 500 tons of ore? 272 The flue gas from the combustion of a hydrocarbon fuel has the following Orsat analysis: 5.66% CO 2, 2.43% CO, 6.4% O 2, and 85.4% N2. The percent excess air supplied is. 30% This is the empirical relation which allows one to compute for the net hydrogen in a given solid fuel. Dulong’s Formula Which of these is not a form of hydrogen present in solid fuels? None of the above
A catalyst increases the rate of a chemical reaction by. Lowering the activation energy of the reaction A certain temperature dependent reaction proceeds 10 times faster at 500 K than it does at 300 K. How much factor will it react at 1000 K than it does at 300 K. 56.23 times faster A gas decomposes at 900 C according to the reaction 2A → 2R 2R 5 with a rate constant of 1000 cm 3/mol-s. Using pure A, the time it will take to react 74.25% of A in a constant volume batch reactor at 900 C and 1 atm in minutes is __. 7.43 A liquid phase double-replacement reaction between bromide cyanide (A) and methylamine takes place in a PFR at 10 C and 101 kPa. The reaction is first order with respect to each reactant, with K A = 2.22 L/mol-s. If the residence time or space time is 4 sec, and the inlet concentration of each reactant is 0.1 mol/L. determine the concentration of bromine cyanide at the outlet of the reactor. 0.053mol/L A liquid polymerization of a certain monomer at constant temperature showed that after 34 minutes conversion is 20% when the initial concentration used is 0.04 mol/L. When the initial concentration used is 0.9 mol/L, conversion is 20% after 34 minutes. What is the specific rate constant for this reaction? 0.0066/min A substance A decomposes by first order kinetics. In a batch reactor, 70% A is converted in 10 min. How much longer would it take to reach 99.9% conversion? 57.4 min In a potential energy diagram, the difference between the potential energy of the products and the potential energy of the reactants is equal to the. Heat the. Heat of reaction In steady-state backmix flow reactor, composition is not. Constant throughout the reactor The homogenous gas decomposition of phosphine 4PH (g) → P (g) → 6H (g) proceeds at 1200 F with first-order rate, r A= (10/hr) C A. What size of PFR operating at 1200 F and 4.6 atm can produce 80% conversion of a feed consisting of 2.75 lbmol phosphine per hour? 160ft 3 The irreversible reaction takes place in a CSTR under the following conditions. FTo = 40 mol/min, C ao = 2 mol/dm 3. The feed is 40% A. K (400K) = 0.1/min and V = 600 dm 3. Calculate conversion of A. 0.87 What is the order of the reaction if the graph C vs t gives a straight line? zero order What is the reaction rate constant for the third order reaction? L reaction? L2 /mol 2-s What plot generates a straight line for a zero order reaction? [A] vs time Which even must always occur for a chemical reaction to take place? Effect collisions bet. reacting particles
A bed consists of uniform spherical particles of diameter 3 mm and density of 4200 kg/m 3. What will be the minimum fluidizing velocity in a liquid of viscosity 3 mPa-s and density of 1100 kg/m 3? 36.4 mm/s A centrifuge with a 20-in diameter bowl, 14-in deep operates at 1200 rpm giving a 2-in thick liquid layer when used with a sludge whose liquid has a specific gravity of 1.2 and a viscosity of 2.5 cp. The solid component of the sludge has a specific gravity of 1.7. If the cut size of the particles is 35 microns, what is the capacity of the centrifuge in gallons per minute? 843 The boiling temperature of ethylbenzene is 136 C. Estimate the enthalpy of vaporization of ethylbenzene at this temperature. 35KJ/mol Oil flows under laminar conditions inside a steam heated copper pipe. The overall heat transfer coefficient is approximately. approximately. Equal to the heat transfer coefficient of the steam 200 mesh screens means. 200 openings/in 2 We must cool 2500 gallons per minute of water from 120 F to 80 F. A cooling tower at 70 F and 1 atm is to be designed to operate with entering air of 40% RH. How many cubic feet per minute of ent ering air must be supplied? 1.61x105cfm Estimate the terminal free settling velocity in air at 20 C if a dust sphere with a diameter of 1 micron and specific gravity of 2. 1.97x10-4 ft/s
Production of potassium, named after a place in US. Trona process Starch has the formula. ( C C 6 6 H 10 10O5 )n Kraft process is a common name for, sulfite for, sulfite pulping The name “rubber” was apparently given by ______, who first observed the ability of the material to “rub out” a pencil mark. Joseph Priestly Produced by fermenting potatoes and then by distillation (Russia). Vodka In the Philippines, sulfur for sulfuric ac id manufacturing is sourced from _______ industry. industry. Paper Production of wet-processed phosphoric acid which uses HCL to acidulate raw phosphate rock then an organic solvent is used to extract the phosphoric acid. Haifa acid. Haifa Which of the following is a lso known as black diamond? Carbonado What is the other for blue gas? Water gas The gasification reaction represented by C + H 2O = CO + H 2, is an a/an. Endothermic
A solution of sodium sulfate in water is saturate at a temperature of 40 C. Calculate the weight of crystals obtained by cooling 100 lb of this solution to a temperature of 5 C. 69.5% (or 69.82%) Calculate the percentage yield obtained by cooling 100 lb of this solution to a temperature of 5 C. 90% The distillation process involves. Heat involves. Heat and mass transfer A mixture containing 60 mols of n-pentane and 40 mols n-heptane is subjected to differential distillation at 1 atm until 40 mols are distilled. Assuming the relative volatility is 8.0, what is the concentration of the distillate? 0.925 Moisture content at which the drying rate first begins to drop. Critical moisture content Consider the frying operations with critical moisture content of 0.10 and an equilibrium moisture content of 0.005 and for a solid loading (db) of 50 kg/m2 with a constant drying rate of 5 kg/m 2-hr. The falling rate of drying is linear with moisture content. The drying time (hrs) required to reduce an initial moisture content of 25% to a final moisture content of 2% is ____. 3.25 If the air leaves the dryer 50% saturated and if the dryer operation is adiabatic, obtain with the use of the relative humidity chart the following: Dew point in F of fresh air. 59.6 Percent relative humidity of fresh air. 58% Humidity in lb water vapor per pound dry air of fresh air. 0.0109 An engineer designed an engine that has an efficiency of 25% and will absorb heat at a temperature of 267 C. Compute the temperature at the exhaust considering that this is an ideal engine. 132 C
A Venturi meter is being used to determine the flow of soyabean oil at 65 C in a pipe. The particular pipe is 15 cm in diameter, which decreases to 6 cm in the throat of the Venturi. The differential pressure is measured as 14 cm of water. Estimate the volumetric flow rate of the soyabean oil. 0.17 m 3h-1 Estimate the mass flow rate of the soyabean oil. 153 kg h -1
Which of the following is an essential amino acid? Methionine acid? Methionine There is DNA or RNA coated protein that ma y or may not be considered as living things. Virus Process in central dogma wherein DNA is replicated in the form of mRNA. Transcription The chemical messenger released by the endocrine gland into bloodstream and transported there to reach its target cell is called ________. Hormones ________. Hormones What is the enzyme present in cheese? Rennin cheese? Rennin An enzyme catalyses a reaction at a velocity of 20 mol/min when the concentration of substrate [S] is 0.01 M. The K M for this substrate is 1x10 -5 M, assuming that Michaelis-Menten kinetics is followed. What will the reaction velocity be when the concentration of [S] is 1x10 -6 M? 1.82x10-6 mol/min These are mixtures of triglycerides containing high proportion of long chain, unsaturated fatty acids or short chain, saturated fatty acids. Oils The microorganism utilized in the production of pickles is. Lactic acid bacteria Which of the following vitamins is lethal in high doses? Vitamin D
What is quickest to become rancid? Butter rancid? Butter The source that fives the highest %CO and NO x emissions to the atmosphere. Transportation facilities The hierarchy of solid waste management i s. Reduce s. Reduce – – Reuse – Reuse – Recycle Recycle – Treatment – Treatment – Disposal Disposal The act of preparing a landfill for long-term inactivity, including placement of a cover over the landfill to prevent infiltration of surface water. Closure Which of the following are the major components of photochemical smog? Ozone and oxygen This is the total amount of oxygen required to oxidize any organic matter present in water, i .e. a fter a n extended period such a s 20 or 30 days. Ultimate BOD Glutamic acid (C5H9 NO NO4) is used as one of the reagents for standard to check the BOD test. Determine the theoretical oxygen demand of 150 mg/L of glutamic acid. Assume the following reactions apply.
C H9 NO 4.5O 4.5O → 5CO 3H O N H NH 2O → NO− H + H O
A sample of radioactive material...0.01% disintegrated after 50 years. What...half-life...material. 8.7 yrs
212mg/L Among...Chalcogen Family, which...non-metallic? Oxygen A liquid generated in landfills is called. Leachate called. Leachate A wastewater treatment plant discharges a flow of 1.5 m 3/s (water plus solids) at a solids concentration of 20 mg/L (20 mg solids per liter of flow, solids plus water). How much solids is the plant discharging each day? 2600kg A 5 mL wastewater sample was analyzed for its BOD content using the standard BOD test. Initial and fifth day dissolved oxygen was measured as 7.5 and 2.5 respectively. What is the BOD of this sample? 300
Arrange...increasing Ionization energy: C(1) Na(2) Mg(3) B(4) N(5). 23415 Arrange...proton,neutron,electron...mass. E
It is used to convert one signal or energy form into another. Transducer It eliminates the offset describe by the proportional controller output. Integral action It is a signal which tends to adversely affect the value of the output of the system. Disturbances system. Disturbances The use of binary (1’s and 0’s). Digital A device that translates the control signal action of the final control device in the process. Actuator process. Actuator A controller whose output is a function of the duration of error. Integral Control Which of the following flow sensors that causes to rotate with an angular velocity? Turbine An inherent disadvantage of this control system is that its results in continuous cycling of the controlled variable and thus produces excessive wear in the final control element. On-off control A 5mL wastewater sample was analyzed for its BOD content using the standard BOD test. Initial and fifth day dissolved oxygen was measured as 7.5 and 2.5 respectively. What is the BOD of this sample ? 300 It refers to the process of maki ng a product of higher-quality that it needs to be to meet specifications. Padding specifications. Padding
Who is the new chairman of PRC? Teofilo Pilando Jr. (But i f Pilando is not in the choices choose Florentino Doble or go to the proctor) Professional Regulations Commission as created under. P.D. No. 223 An integrated national professional organization that is duly accredited and recognized by the corresponding Board and the Professional Regulations Commission is referred to as. Accredited Professional Organization The new chairman and new commissioner of PRC were both sworn into office on _____. December 9,2014 A section of the patent application containing detailed descriptions of the benefits obtained from using the invention is called. Claims The design of the dry seal that is required of chemical engineering in order to practive the profession must be authorized by: Board of Chemicals The new PRC commissioner is ______. Architect Yolanda Reyes RA 9297 is also known as. Chemical engineering Law of 2004 The keystone of professional conduct is. Integrity The members of the Board of the Chemical Engineering are empowered to decide on which of the following cases brought before them. None of these
Balmer series (m (m=2). 27434 cm -1 Brackett series (m= (m=4). 4). 6859 cm-1 Change in energy...electron is accepted by a gaseous atom to form an anion. Electron anion. Electron Affinity Compound...molecules...not (CH 3 ) )3COCH 3
associated...hydrogen
bonding
is.
Consider the reaction: PCl 5(g) PCl3(g) + Cl 2(g) ΔHθrxn = 87.9 kJ/mol. Which...will result...increase...concentration of Cl 2 gas? Add gas? Add PCl 5 Consider...1600°C: Br 2(g) 2Br (g) 2(g) (g). When 1.05 moles of Br 2(g)...2 L flask, 2.50% of Br 2...dissociation. Calculate... K p for the reaction. 0.020689 Constant...fundamental number of hydrogen is. Balmer constant Equivalent to the rate of disintegration of 1 gram of radium. Curie Half-life of later? 0.09
90
Sr is 29 years. What fraction...would remain 100 years
If 23892U...decay...produce 23490Bi, what...particle was emitted? Alpha emitted? Alpha Minimum wavelength of light...work functions. Li( ϕ = 2.90 eV). 428 nm Ge(ϕ Ge(ϕ=5.00 eV). 248 nm NaClO2 is. Sodium chlorite Osmotic pressure of a dilute aqueous ethyl alcohol solution at 25°C is 38 mmHg. Calculate...boiling point elevation...solution. 0.0011°C Oxalic acid + sodium hydroxide. Na hydroxide. Na2C 2O4 Pertains to single bond, double bond, triple bond... Between single and double bonds, etc. Bond etc. Bond Order Potassium-40 decays to argon-40 with half-life of 1.27 x10 9 years. What...age of the rock...mass ratio of 40Ar to 40K is 4. 2.9 4. 2.9 x10 9 years Quantum number...allowable value of 0,1,2, etc. Angular Momentum Quantum Number Ra-226...alpha emission. What...decay product?
222 Rn 86
Radium-226, which undergoes undergoes alpha decay, has a half-life of 1600 years. How many alpha particles are emitted in 10 min by 10 mg sample of radium-226? Assume 1 year to have 365 days. 2.2 x 10 11 Region in space...electron is most likely to be found. Orbital
Rutherford’s experiment, which is true. The atom is almost an empty space. Speed of an electron...Rb(ϕ electron...Rb( ϕ = 2.16 eV) when 350 nm...vacuum. 7.00 x 10 5 m/s Starting... 1.000 gram of Sr-90, 0.953 gram will remain after 2 years. Calculate...initial activity of Sr-90 in Ci? 1 Curie(Ci) = 3.70 x 10 10 disintegration/sec. 140
States...no two atoms will have the same set of quantum #s. Pauli’s Exclusion Principle +2
Sum of # of protons,neutrons and electrons...zinc ion, Zn . 93
A binary solution, where A is a low boiler exhibting a maximum boiling point, is subjected to flash distillation. If the feed has a concentration in A less than the azeotropic point, the concentration of the distillate will be. Higher be. Higher in B A debutanizer is a. Mass a. Mass transfer equipment A distillation column with a partial condenser is composed of 7 theoretical stages in the rectifying section and 8 theoretical stages in the stripping section. If the overall plate effeciency is 60%, the the actual feed plate is. 11th A heat transfer equipment to convert vapor to liquid is an/a. Condenser A liquid mixture...45% benzene and 55% toluene by weight is to be fed to a fractionating column at a rate of 5000 kg/hr. The feed feed rate in kg mol/hr is. 58.74
Type of equilibrium...similar phases is called. Homogeneous called. Homogeneous equilibria Vapor pressure of water at 25°C is 23.756 torr. A solution... 18.913 grams...non-volatile...36 grams of water...vapor pressure of 20.234 torr. What is the molecular weight of the solute? 56
A reboiler provides heat to the. The bottom of a distillation column
What group...electron configuration?[Ar] 4s 23d104p3. 5A
Desorption is another tem for. Stripping
What....activity... mCi? (1Ci = 3.7 x 10 10 disintegration/atom-sec). 99 mCi
For a mass tranfer to take place, there must be. Concentration gradient
What...binding energy per nucleon for C -13 (13.003355 amu) in MeV? 7
For a non-azeotropic solution being distilled, the temperature in the distillation column, from bottom to top. Decreases top. Decreases
What...freezing point of a 0.205 molal solution...urea (60 g/mol) when 200 grams...250 grams of water? -0.168°C What...freezing point...30% wt urea, (NH 2)2CO solution in water? 13.29°C
-
What...max number of electrons...atom...quantum number: n=2, m s= -1/2. 4 Which...acidic oxide? SO2 Which...following sets...quantum numbers...incorrect. n=1,l=0,ml =-1, m s=-1/2 -2
At minimun reflux ratio, the number of plates is. Infinite is. Infinite
For nearly pure products in a stage operationg, the theoretical number of plates may be estimated using the. Tiller-Tour Equation If the enthalpy os saturated vapor at 200 °F reffered to 32°F 32 °F 1300 BTU/lb while the enthaply os saturated liquid (C p = 1) referred to 0°F 0 °F is 400 BTU/lb, then the latent heat of vaporization of the component at 200°F 200°F is. is. 932 BTU/lb If the HETP of the column of previous problem is 2 ft the the height of an equivalent packed column is. 26 ft In a distilling column, the highest pressure will be at. the bottom
-1
Which...isoelectronic. S and Cl
Which...its K p equal to its K c? H2(g) + I2(g)
2HI(g)
Which...molecules/compounds is formed by covalent bonds? NO2 Which...most electronegative? F electronegative? F Which...particles cannot be accelerated in a particle accelerator? Neutron Which...properties do not depend...electronic configuration...atoms. Nuclear Which...will have the highest boiling point elevation? Na elevation? Na2SO4
In a simple batch distillation, the boiling point of the distillate product compared to residue is. Lower is. Lower In a two-component. Flash distillation process, when the operating pressure is specified, the concentration of the distillate may be improved in the more volatile component if. The operating temperature is decreased In a vacuum distillation column the vacuum is usually created by a. Vacuum pump In batch open distillation, the solution t o be open steam distilled should be. Completely immiscible in water In distillation, the cooled liquid stream returned to the column to cool a plate or stage is called. Reflux called. Reflux
A 50% by weight benzene-toluene mixture is fed to a column at 180 °F and 1 atm. The condition of this feed is. Sub cooled liquid
In distillation, where there are two components and both components are found in both phases, only one variable variable such as liquid phase concentration can be changed independently if the pressure is fixed and the remperature and vapor phase concentration will follow. This statement is. True
A binary mixture of 2 moles benzene and 8 moles toluene will boit at. 102°C
Increasing the operating pressure of a distillation column. Make separation difficult
McCabe-Thiele method to determine the theoritical number of stages may be applied with acceptable result if. the system follow Trouton’ s Rule
The unit operation by which the lighter components in a multicomponent solution of a volatile liquids are separated from the heavier components is called. Distillation called. Distillation
One hundred moles per hour of solution contating 80 moles of A, the rest B is subjected...simple continuous distillation. D moles of distillate...72 moles A is obtained. If A is five times more volatile than B, the concentration of A in the distillate is. 0.85
To improve the degree degree of separation of thee more more volatile component from the less volatile component through distillation, the chemical engineer may, without changing the other variables. Reduce variables. Reduce the column pressure
Open steam binary rectification may be applied with the success if the less volatile component is. Water
Using Antoine’s equation, the vapor pressure of tetrahydrofuran at 80°C 80°C is estimated to be at ___ torrs. 1173
Strictly speacking, the relative volatility of most ideal binary solutions is. Slightly affected by temperature
Vacuum distillation is resorted to in order to. Avoid high feed and reboiler temperatures
The activity coefficient of a component in a non-ideal liquid solution at low pressure is approximated to be equal to. None to. None of these
When the feed to the rectifying column is a saturated liquid, the feed line is. Vertical
The approximate minimun number of stages for a binary system with relative volatility of 2.35, fractionally distilled to yield compositions of 0.98 in the distillate and 0.045 in the bottom is. 8.1
When the molal latent heat of vaporization of the binary system is very much dependent on concentration, the most appropriate method to use to determine the number of ideal stages is. Ponchon-Savarit is. Ponchon-Savarit Method
The degrees of freedom associated with a ternary distillation process, according to the Gibbs’ phase rule, is. 3
When the relative volatility of two miscible components close to 1.00, the components can be separated by. Extractive distillation
The difference between stage operation (A) and a continuous phase contact operation (B) is that. (A) that. (A) yields discreet concentration changes while (B) yields infinitesimal concentration changes The distillation process involves. Heat and mass transfer The distribution coefficient of n-hexane at 10 atm abs and 200 °C is. 1.4 The ease or difficulty of separating components by distillation is determined by the. Relative the. Relative volatility The percentage change in the boiling point of a 20-mole benzenetoluene solution when the pressure is increased from 1 a tm to 2 atm is. 25.5% increase The physical separation of components in a miscible mixture by simultaneous evaporation and condensation is. Distillation is. Distillation The primary reason why close steam is used in an open batch steam distillation is to. Increase to. Increase the number of degrees degrees of freedom The recent availability of digital computer resulted in the development of many analytical expressions for the evaluation of K-values. Which of the items below is a source of analytical method for K-values? All of these The relative volatility of the mixture at the azeotropic point where the solution exhibits minimum boiling point is. Equal is. Equal to 1 The temperature of the solution in problem 2 as distillation progresses at constant operating pressure. Constant The theoritical minimum reflux ratio in a distillation column is attained if the column has. An has. An infinite number of plates The total actual number of plates of the distillation column of the previous problem is. is. 22 The unit operation by which miscible liquid are separated from on another through heat and mass transfer is. Distillation is. Distillation
A chemical engineer was commisioned to design vertical cylindrial with a flat bottom and a conical roof. The tank...height of 16.5 m...tank cylinder. Normal...90% of the total tank volume. The tank roof has a 10% incline. Suitable... 4’ x 8’ sheets. The number of sheets needed is. 540 A cylindrical water tank with a hemispherical dome has the dimensions shown below.(pic) the tank is full. The t otal force, in lbf, extered by the water on the base of the tank is most nearly. 590,000 A horizontal cylindrical tank is used for the storage of motor gasoline...Pandacan. The tank...inside diameter of 3m...inside length of 10m. The suction...30 cm...sludge. To prevent overfilling, the maximum height...exceed 90% of the vertical height. The working capacity of the tank in kiloliters is. 63.32 A major classification group of stainless steels 6% to 22% nickel in addition to 16% to 26% chromium. This group differs from the other two major groupings in that steels. Are non-magnetic A reactor will operate at 300 psi and 600°F. 600°F. Height = 12 ft; crown radius = 66 in; diamter = 6ft; double welded butt joint, efficiency = 80%. Allowable tensile strength of material i s 12,000 psi. The thickness of the shell is. 1-3/16” 1-3/16” A spherical carbon steel storage tank for ammonia...diameter of 30 ft. All joints...backing strip. If the tank...pressure of 50 psig... 80 °F, estimate...wall thickness. Assume no corrosion is necessary, efficiency...80%...tensile strength...13,700 psi. 7/16 in A thin wire is subject to a tensile stress. If the temperature is constant, the electric resistance of the stressed wire with respect to the electric resistance of the unstressed wire will. Increase will. Increase A water tank 30 ft. in diameter...3/8 inch thick. Assume the allowable stress of steel is 15,000 psi and a joint efficiency of 80%. Provide a corrosion allowance of 1/16 inch. The maximum height of the water tank is. 48.03 ft
Bracket supports are most suitable for. Thick walled vertical vessels Circular cylindrical cans of volume V o are to be manufactured with both ends closed. The ratio of the diamter and height that will require the minimum amount of metal to make in each can is. D/h = 1.0 Four inch (4.0 inch) shedule 40 steel pipes are to be used to transport high pressure steam. The pipe joints are to be butt-welded. The safe working fiber stress for butt welded pipes is 457.1 kg/cm 2. The maximum steam pressure in, kg/cm2, the pipes can handle is. 18.28 kg/cm2 If an engineering structure is to be designed against rupture of any of its members under steady load, the factor of safety is a ratio based on working stress and. Ultimate strength In the construction of a vinegar tank, one of these metals of construction is not recommended. Brass recommended. Brass Normally the dia mter of a rivet is 1/16 in. less than that of the hole in which it is to fit. This is to ensure easy entrance of a hot rivet. In boiler calculations, the rivet is assumed to. Fill to. Fill the hole after driving Skirt support is most suitable for. Tall horizontal vessel The Brinell Number of a material is a measure of. Hardness The chief difference between exterior grade plywood and interior grade plywood is. That is. That different types of glue are used The intermittent welds generally used to hold material in place temporarily are called. Double called. Double vee The offset method is used to find a property of metals that do not have a well-defined stress-strain curve such as steel. This property is called the. Yield point The only strength of stress grade lumber that can be precisely determined without breaking the piece is. Stiffness The stress in an elastic material is. Proportional is. Proportional to the displacement of the material acted on by the force The thickness of the head is. 3/2” The ultimate strength divided by the allowable stress i s. Factor s. Factor of safety safety
Absolute zero maybe regarded as the temperature at which. Molecular which. Molecular motion in a gas would cease In the reaction of Fe 3O4 with C to form CO 2 and Fe, the number of moles of carbon required to convert 23g of Fe 3O4 to product is. 0.2 Tyndall effect is shown by. Colloidal solution What is the concentration of Cl - in a solution that contains 35ppm chloride? 3.5x10-3% H2 + I2 2HI. If the pressure is increased by reducing the volume of the flask. The amount of HI will remain the same Determine the number of moles of aluminum in 2.154x10 -1 kg of Al. 7.984 mol Write the symbol of the species with 28 protons, 26electrons, 32 neutrons. 60 Ni2+ Arrange the following according to increasing ionization energy. Na
The unit lateral deformation of a body under stress divided by the unit longitudinal deformation is known as. Poisson’s as. Poisson’s Ratio Ratio Warp, wane and checks are all factors that help determine the quality of. Stress grade lumber
What is the name of the compound or Cyclohexylpropyl ether
? 1-propoxycyclohexane
Which of the following contains sp -hybridized carbon? C 5 H H 8 An endothermic reaction is one in which. Heat which. Heat is absorbed
Which of the following is the ester formed from a two carbon alcohol and a five carbon acid? Ethyl acid? Ethyl pentanoate
Which of the following has the largest radius? C Data: -890.3 kJ
It is the bond formed in the head-on overlap of two orbitals? Sigma
Which of the following species is not isoelectronic with any other? V 3+
Which of the following alkenes is gas at room temperature? Propane temperature? Propane
Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide. If 150g of NH 4I is placed into a 3-L vessel and heat ed to 400C, calculate the partial pressure of ammonia when equilibrium is reached, k p= 0.215. 0.46 atm
Choose the incorrect statement CH3CH2CH2CH2CH2 NH NH2 is an amine CH3CH2OCH2CH2CH3 is an ether CH3CH2CH2CH2CH2OH is an alcohol
CH3CH2CH2CH2CH2O is ketone When ethyl bromide is treated with sodium in dry ether, the product is. Butane
What is the correct name of the molecule 2 – bromo – bromo – 3 – 3 – chlorobutane chlorobutane
. (2R,3S) – (2R,3S) –
According to Markovnikov’s rule, addition of HBr to 2 -pentene will give. Both give. Both 2 – 2 – bromopentene bromopentene and 3 – bromopentene bromopentene How many isomers does xylene have? 3 2-methyl, 3-pentanol
A metal reacts with water with the evolution of hydrogen hydrogen and formation of its hydroxide. One mole of the metal was allowed to react completely with water. The hydroxide solution formed was made up to one liter. One hundred mL of this solution require 110 mL of 0.9091 N HCl for neutralization. The chloride of the metal was found to contain 13.7% chlorine. The volume of hydrogen gas liberated at STP is. 11.2 L The L The atomic weight of the metal is. 224 Since 224 Since the solution of the hydroxide of the metal is normal, the valency of metal i s. 1 A 1.208-g sample of impure Na 2CO3 is dissolved and allowed to react with solution of CaCl 2. The resulting CaCO 3, after precipitation, filtration, and drying was found to weigh of the precipitate, calculate the % purity of Na 2CO3. 91.1% The color of Cu in the flame. Bright flame. Bright green Calculate the pH of a solution necessary to just begin the precipitation -11 of Mg(OH) 2 when [Mg 2+]=0.001 M. k sp spMg(OH)2=1.2x10 . 10
Which of the following will distinguish 1-propanol from 2-propanol. Lucas Test Natural rubber is a polymer of. of. Isoprene Isoprene Which of the following carbonyl compounds produce a secondary alcohol with LiAlH8? Ketone Williamson Synthesis is the procedure for producing. Alkanes using sodium metal Which compounds are isomers? 1 – propanol propanol and 2 – propanol propanol Which of the following alkynes contain a cidic hydrogen? Propyne hydrogen? Propyne Compounds with general formula (C 5H8)n. Terpenes Oxidation of isopropyl alcohol with potassium permanganate yields. Acetone Calcium carbide on interaction with water gives. Acetylene gives. Acetylene
The roasting of 100 g of a copper ore yielded 75.4 g of 89.5% pure copper. If the ore is composed of Cu 2S and CuS with 11% inert impurity, calculate the percentage of Cu 2S in the ore. 62% A proton donor is. Bronsted-Lowry Acid What is the pH of a buffer prepared by adding 180 mL of 0.100 M NaOH to 200 mL of 0.100 0.100 M acetic acid (k a=1.8x10-5). 5.70 What is the pH of a 0.10 M solution of (HNO 2)? 2.09 Which of the following solutions results in a buffer pH = 4.0? Assume that the ka value of benzoic acid is 6.5x10 -5. 0.16 M benzoate and 0.25 M benzoic acid With the presence of Pb 2+ ion, what is the color of its precipitate? Yellow In a 0.1 M HF solution, the percent dissociation is determined to be 9.5%. calculate k a,. 1x10-3
Which of the is not a correct analytical method-titrant pair? Volhard AgNO3 It is an ion that bears both positive and negative charge. Zwitterion Consider the titration of 50mL of 0.1M HBr with 0.1M KOH. Calculate the pH of 49mL of the base that has been a dded to 50mL of HBr. 3.0 If 1.000g mixture of Cu 2O and CuO is quantitatively reduced to 0.865g of Cu. The mass of Cu 2O in the original sample of the mixture must have been. 0.742g Silver chromate, Ag2CrO4, is soluble to the extent of 0.0259 mol/L. Calculate the solubility product constant. 2.5x10-4 9.6x10-5 6.7x10-4 6.9x10-5 A sample containing NaBr and KBr only weighs 253.03mg. The sample was dissolved in water and treated with AgNO3. The precipitate formed was found to weigh 429.85 mg. Calculate the %NaBr in the sample. 49% When 5.50g of biphenyl (C 12H10) is dissolved in 10g benzene, the boiling point increases by 0.903 C. What is the k b b of benzene in K/molal? 2.53
Given the mass defect for the triton (tritium nucleus) to be 0.00910 amu, calculate the energy per nucleon. 2.825 MeV Water has surface tension of 0.4 N/m in a 3mm diameter vertical tube if the liquid rises 6 mm above the liquid outside the tube. Calculate the contact angle. 83.7
Calculate the mass of water in grams that could be heated from 20 C to 100C by the energy generated by an electric current of 10A across a voltage of 10V for 10 hours. 10,755 The rate of decay of 79Au195 is such that 79.8% of a sample of this nuclide remains as 79Au195 after 60 days have elapsed. What is the halflife of 79Au195? 184.31 days
The radioactive isotope C-14 has a half life of 5720 years. As a result of the natural abundance of C-14, a 1g sample of carbon from a living organism undergoes 15 disintegrations/minute gram. How old is a 10.0g sample for which the rate is 0.91 disintegrations/minute gram? 4120 years An atom which undergoes a nuclear reaction resulting in an increase in atomic number has emitted. β particle particle In an electrolytic cell, how many grams of Cu could be plated out of a CuSO4 solution at a current of 5.00 A for 2 min? (F=96,500 C/mol). 0.198g What is the electrical work done by 3.00 moles of electrons at a potential of 1.75V? 5.07x105 J This states that “For solid element (with few exceptions), the product of atomic weight multiplied by specific heat (atomic heat) approximates a constant value of 6.4”. Dulong 6.4”. Dulong and Petit’s Law
A total of 165 J of work is done on a gaseous refrigerant as it undergoes compression, if the internal energy of the gas increased by 123 J during the process, what is the total amount of energy transformed as heat? 42 J Helium is compressed isothermally from 14.7 psia and 68 F. The compression ratio is 4. Determine the change in entropy of the gas in BTU/lbF. -0.689 If one mole of silver weighs 108 grams and its heat of vaporization is 250 kJ/mol, how much energy is given off if 20 grams of silver are condensed to liquid at its boiling point? 46 kJ The Carnot engine are operating in series. The first one absorbs heat at 1,111 K and rejects heat to the second engine at temperature T. The second engine received the heat at the intermediate temperature T and rejects it to a reservoir at 300 K. Calculate T if the efficiencies of the two engine a re equal. 577 K
The molecular diameter of CO i s 3.19x108 cm at 300K and pressure of 100mmHg. What is the mean free path of the gas in cm? 6.86x10-6 The difference between the heat of combustion of methane at constant pressure and at at constant volume at 27C when the liquid water forms is -1192.2 cal -2314.5 cal 1257.4 cal -1257.4 cal The Van der Waals constants for HCl are a=3.67 atm-L 2/mol2 and b=40.8 mL/mol. Find the critical constants constants of the substance. 81.65 atm, 324.83K All of the following are true a bout crystals except. A except. A crystal softens softens and melts over a wide range of temperature What is the lowest possible temperature of matter? Absolute matter? Absolute zero What current would be necessary to deposit 1.67g of Fe(s) from a solution of Fe 3+(aq) in 1 hour? 2.40A What is the potential cell for Zn/Zn 2+ (0.01M//Ag +(0.1M)/Ag? The standard cell potential is 1.562V? 0.763V or 0.263V (dilimaklaro HAHAHA) 1.473V 0.749V 1.6V What is the wavelength of radiation that has a frequency of 5.11x10 11 Hz? 5.87 x10-4 m The ability of gas that tends to expand indefinitely into a vacuum or another. Diffusion another. Diffusion Benzene boils at 80 C under normal conditions and diethyl ether at 34.6C. At what temperature does the benzene have the same vapor pressure as does the ether at 25C? 69 C
Calculate T if the work done by the two engines are equal. 705 K A heat engine absorbs heat from the combustion at 2200 C. The gasoline has a specific gravity of 0.80 and heat combustion of 11200 cal/gal. The engine rejects heat at 1200 C. The maximum work is in calories that can be obtained from the combustion of 1 liter of gasoline is. 3.62 x10 6 cal During the adiabatic reversible expansion of an ideal gas, the amount of heat absorbed by the gas is equal to. Zero to. Zero At standard temperature and pressure, what is the heat of formation of water vapor? -241.82 kJ For an ideal gas what is the specific molar entropy change during an isothermal process in which the pressure changes from 200 kPa to 150 kPa? 2.39 J/mol-K How is conservation of internal energy expressed from system during an adiabatic process? Q = 0, So U = -W A closed gaseous system undergoes a reversible process during which 25 BTU are rejected, the volume changing from 5 ft 3 to 2ft 3 and the pressure remains constant at 50psia. Find U. U. 2.76 BTU What is the unique state at which solid, liquid, gaseous phases co-exist in equilibrium? Triple point A 5-lb block of copper at 200 F is submerged in 10 lbm of H 2O at 50F and after a period of time, equilibrium is established. If the container is insulated what is the entropy change of the system? 0.0167 BTU/ R
1 kg of water (C=4.2 kJ/kg K) is heated by 300 BTU energy. What is the change in temperature in K? 75.4
Which of the following completely fills the blank in this nuclear reaction? 8 Be
Which of the following thermodynamic quantities gives a finite quantity when integrated? Heat integrated? Heat How much energy in (kJ) is required to vaporize 0.5 kg H 2O which is originally at 24 C and 1 atm? 1287.57
If ΔG < 0, then. A then. A spontaneous reactions is possible possible
The net work accomplished by an engine undergoing adiabatic compression is equal to. – to. – ΔU
A diesel engine has a compression ratio of 20:1 with an inlet of 95 kPa, 290 K, state 1, with volume of 0.5L. The maximum cycle temperature is 1800 K. Find the maximum pressure. 6298 kPa. kPa . Find the net specific work. 220.5 kJ/kg
It is unethical to undervalue ones professional services compared with others just to get a given contract. True An invention that is for public good could be developed even without the permission of the inventor especially if he refuses to license the invention for a reasonable royalty. False royalty. False Two countries can allow their professionals to practice even without a license provided there is a reciprocity agreement. True A chemical engineer can do work of a chemist. True The act regulating the practice of ChE in Phil. RA Phil. RA 9297
Organization of ChE accredited by PRC. PIChE The PRC has supervisory power in BOChE. True 55 % ChE, 50 % in Phy. and Chem., 90 % in Gen. Engineering. Fail the exam No one can practice ChE unless licensed by BoChE. True Doctorate degree can secure license without examination. False examination. False Foreigners who on the date of the approval R.A. 6511 had been practicing chemical engineering law are exempt from the registration. False A chemical engineer who designed and built a new reactor and for three years sold many units to the public can still patent his reactor. True A ChE can review the work of another ChE without his permission for the same client. False client. False It is right to compete with another ChE provide ed inadequate compensation is made. False made. False
A chemical engineer must be guided in his profession and relationship with others by The highest standard of honor and integrity. Specifications means. All means. All of these To publicly criticize work of another ChE is allowed or ethical. False An employee can claim exclusive ownership of an invention produced during his employment in a c ompany. False ompany. False A foreign ChE is allowed to practice in Phil. If requested by the Phil. Government. True The New Code of Ethics for the Practice of ChE was approved by BoChE in 2009. The BoChE may inspect the facilities, faculty, equipment and other aspects. CHED A chemical engineer who violates the provisions of ChE Law, upon convivtion, 5 years. The ChE shall report any infraction PRC infraction PRC
Exchange of information among ChEare allowed except for confidential information. True
New Intellectual Property Code, RA 8293, January 8293, January 1, 1998
The ChE can work only in Unit Operations. False Operations. False
Compositions or forms giving distinct appearance pattern in a product can be protected as industrial design
ChE are guided by RA by RA 9297. A foreign ChE can practice ChE in Phil. Phil. Provided he is given exemption by PRC. by PRC. The life of patent is 17 years. To be a ChE board examiner, one must be at least 30 years of age. True As a general rule, a foreign ChE can practice his profession in Phil. False
Copyright works are protected during the life of the author and 50 years after his death. death. According to ChE Law of 2004, at least one ChE shall be included in the personnel of . All All of these Approved patents are published in IPO in IPO Gazette A document issued by DENR, EIA. It is the meeting of the mind between two persons Contract.
Term duty of BoChE is 3 years only. True
It is a juridical necessity to give Obligation
The PRC formulates the examinati on questions. True
Not essential element of contract. Declaration contract. Declaration of third party
Changing the process of a patented invention without the inventor’s permission is an act of infringement. False infringement. False
Not cause of inexistence and nullity of contracts. Those are which previously ratified by the contracting parties
A BochE Examiner should not be connected with a school where he has a pecuniary interest. True
Contract wherby the debtor,s property is given as a security for his debt . Mortgage
The PRC Modernization Act of 2000. RA 8981. Serves as a collective recognition by members of a profession of its responsibilities. Code of Ethics Unethical for a chemical engineers do. Compete with another engineer unfairly Why we support the Code of Ethics? All Ethics? All of these When there’s an engineer’s conference and an engineer was asked to give additional information and suggestions, what is the right thing to do? He should voice out his knowledge about the topic and make suggestions
M in water, 9 kg of S , X/Z= 3% M that will remain . Single batch= 25%, two successive= 16.6 % Benzoic acid is 9 times more soluble in chloroform than water. % benzoic will remain . Each quantity of chloroform= 10 %, twice as much as chloroform= 5.3 %, if followed by two extraction= 0.35 % Acetic acid by isopropyl alcohol. F= 10,000 kg/hr of 28 % acetic acid. S= 30,000 kg/hr, E= 8% acetic # of stages = 8 Solvent to feed ratio= 1.75
Concepts What is the name of the compound? 1-propoxycyclohexane or To determine the minimum ratio of extraction solvent to feed solvent, one has to know The distribution coefficient.
Cyclohexylpropyl ether Which of the following contains sp -hybridized carbon? C 5 H H 8
In LLE process, extraction solvent has no selectivity when the ratio of the two component. 1.0
Which of the following is the ester formed from a two carbon alcohol
In an extraction process the greater the weight of solute. The more is.
It is the bond formed in the head-on overlap of two orbitals? Sigma
Unit operation by which soluble components of a liquid mixture are dissolved in another liquid. Solvent extraction LLE is based on Solubility. Heat sensitive materials with high heat of vaporization Liquid vaporization Liquid extraction.
and a five carbon acid? Ethyl acid? Ethyl pentanoate
Which of the following alkenes is gas at room temperature? Propan temperature? Propane When ethyl bromide is treat ed with sodium in dry ether, the product is. Butane What is the correct name of the molecule. ( 2R,3S) – 2R,3S) – 2 2 – bromo bromo – 3 3 – chlorobutane
Fractional solvent extraction. Employs extraction. Employs 2 solvent Selectivity of solvent. >1 In liquid extraction, if selectivity is unity. No unity. No separation will occur When the solvent dissolves very little of the solute then. Large then. Large quantity of solvent is required to extract the solute
According to Markovnikov’s rule, addition of HBr to 2 -pentenewill give. Both give. Both 2 – 2 – bromopentene bromopentene and 3 – bromopentene bromopentene How many isomers does xylene have? 3 2-methyl, 3-pentanol
Most suitable for extraction having very low density difference. Centrifugal extractor In extraction, as the temperature increases, the area of heterogeneity. Decreases Solution of solute A in diluent B mixed in solvent S, extract Rich S, poor in B, rich in A Problem 30 kg solute, 100 L water, 35 L ether, K=4 mass solute=2.45 kg If 3stage counter current extraction. Mass extraction. Mass solute= 27 kg Extract benzoic acid from toluene using water, benzoic acid =10 %, toluene = 90 % Rate of feed= 120 gpm, rate of solvent= 20gpm K=0.125 % of the acid extracted. Single stage= 59%, 2 stage= 79 %
Which of the following will distinguish 1-propanol from 2 propanol. Lucas propanol. Lucas Test Natural rubber is a polymer polymer of. Isoprene of. Isoprene Which of the following carbonyl compounds produce a secondary alcohol with LiAlH8? Ketone Williamson Synthesis is the procedure for producing. Alkanes using sodium metal Which compounds are isomers? 1 – propanol propanol and 2 – 2 – propanol propanol Which of the following alkynes contain aci dic hydrogen? Propyne hydrogen? Propyne Compounds with general formula (C 5H8)n. Terpenes
Oxidation of isopropyl alcohol with potassium permanganate yields.
The following reagents will yield an alkyl halide from an alkene except
Acetone
Br 2 /UV or light
Calcium carbide on interaction with water gives. Acetylene gives. Acetylene
The acid-catalyzed addition of water to 1-butene will form 2-butanol The rule which states that, “In the addition of HX to alkenes, the halogen
REVIEWER
attaches to the doubly bonded carbon with more alkyl substituent.”
Which of the following contains sp -hybridized carbon? C 5 H 8
Markovnikoff’s Rule
Bond formed in the head-on overlap of two orbitals. sigma
Starting with 2-methyl-2-butene, which of the following processes must
Part of a molecule where most of its chemical reactions occur.
be used to produce a secondary secondary alcohol? Hydroboration-oxidation alcohol? Hydroboration-oxidation
Functional group
Which of the following reagents will yield a diol from a given alkene?
Which of the following molecule is unsaturated? C 5 H 10 10
OsO4 in NaHSO4
Name the alkane. 2,3,4-trimethylhexane
Hydrogenation of alkynes in the presence of a poisoned palladium catalyst produces alkene Addition of HBr to alkynes results i n the formation of germinal of germinal dihalide dihalide When 2-butyne undergoes ozonolysis, the main product is acetic acid
Which of the following alkanes is gas at room temperature? propane temperature? propane When ethyl bromide is treated with sodium in dry ether, the product is butane
In hydration of alkynes, the enol formed is found to transform into a ketone. This form of isomerism i s known as keto-enol tautomerism Name the alkyne: 4-methyl-2-butyne
For the following alkanes, the one with the lowest boiling point is 3.
Which of the following alkynes contain aci dic hydrogen? propyne hydrogen? propyne The following reagents will produce an alkane from an alkyl halide
Among the molecules, which is not aromatic?
except alcoholic KOH How many possible monochlorinated product is expected from the chlorination of propane? 2
All of the following are ortho and para directing substituents except –
Name the alkene: 2-methyl-2-butene
NO2 How many isomers does xylene have? 3 Vinylbenzene is also known as styrene
The name of the saturated hydrocarbon isomer of cis-3-hexene is cyclohexane For which of the compounds below are cis -trans isomers possible? Both possible? Both
Which of the following carbonyl compounds produce a secondary alcohol with LiAlH4? ketone Addition of methyl magnesium bromide to acetaldehyde produces 2 propanol
2 and 3 When 1-bromo-2-methylcyclobutane is treated with alcoholic KOH, the dominant product is
Oxidation of isopropyl alcohol with KMnO 4 will yield acetone Which of the following alcohols will undergo bimolecular nucleophilic substitution? 1-propanol In Williamson synthesis of methyl isopropyl ether, the alcohol used is isopropyl alcohol
Among the following alcohols, methylpropene can be obtained from 2-methyl-2-propanol Alkenes are commonly prepared via elimination reaction, which of the following is not an elimination reaction? Hydrogenation reaction? Hydrogenation of alkynes
Acid-catalyzed ring opening of an epoxide will result in the formation of a/an dihydric alcohol Which is NOT a physical property of alcohols or phenols? The hydroxyl group of an alcohol is non-polar
Hydrocarbon derivatives used as a main ingredient in automobile
It was first used as an anesthetic in 1824. It produces unconsciousness
antifreeze. Ethylene antifreeze. Ethylene glycol
and insensitivity to pain by inhibiting activity of the central nervous
Which of the following will distinguish 1-propanol from 2-propanol?
system. Diethyl system. Diethyl ether
Lucas test
They are a class of cyclic ethers in which the ether oxygen is included
The following reagents will give an alkyl halide from alcohol except
in a three-membered ring. epoxides
NaCl
The acidic ingredient in vinegar and the pure acid is useful solvent and
Which among the following is a ketone? CH 3COCH 3
manufacturing intermediate. Acetic intermediate. Acetic acid
Which of the following processes will yield a n aldehyde? Ozonolysis of
These are different compounds that have the same molecular formula
alkenes
but different structural formula. isomers
A tertiary alcohol is produced using Grignard Reagent using a/an ketone
This geometric isomer indicate that a particular group are on the same
Carbonyl compounds can be obtained by reduction using the following
side of the molecules. Cis-isomer
except amide
Which of the following statements is FALSE regarding the reaction
Addition of hydrazine to carbonyl compounds produces a/an hydrazone
between Cl2 and C 2H6? The reaction will give a single product of C 2 H 5Cl
Reduction of alkyl phenyl ketones to aromatic hydrocarbons done by
What is the expected product formed from the reaction between 2-
Wolf-Kishner Reduction uses NH uses NH 2 NH NH 2 ,KOH
butene and Cl2? 2,3-dichlorobutane
With the same molecular weight, a carboxylic acid will have a/an higher
The most acidic hydrogen in an alpha carbon occurs in alkyne
boiling point than an alcohol.
A carbonyl group occurs in all of the following except ether
Acid anhydride upon hydrolysis yield carboxylic acid
The reason why some alcohols are soluble in water. Hydrogen water. Hydrogen bonding bonding
Hexanedioic acid is also known as adipic acid
Which of the following alcohols will undergo a 1,2 -methyl shift when it
Reaction of alcohol and a carboxylic acid is known as esterification
is heated with acid? 3-methyl-2-butanol
Name the acyl halide: butanoyl chloride
The interconversion between the keto and enol forms is a special kind of isomerism. tautomerism The reaction of carboxylic acids in their conversion into esters by reaction with an alcohol (the substitution of an – OH OH group with an –
Addition of an alcohol to acyl halides produces ester
OR). Fischer OR). Fischer esterification
Name the acidic anhydride: acetic propionic anhydride
Ethers can also exists as cyclic molecules. epoxides The addition of alcohols (in excess) to aldehydes yields this product. acetals It is the reaction when an enolate ion is prepared from an aldehyde,
Addition of ammonia to acid anhydrides produces amide Name the ester: ethyl propanoate
remaining un-ionized aldehyde is attacked by the formed enolate ion. Aldol Condensation It is the reaction of sodium alkoxides with alkyl halides producing an ether. Williamson synthesis In the reaction of 1-bromooctane with thiourea, what product would you
An unknown ester was hydrolyzed with water and acid to produce an
get? Octanethiol
acid, X and alcohol, Y. Oxidation of the alcohol with hot KMnO 4
How would you prepare pentanal from pentanol? Oxidation using PCC
yielded acid X. Ozonolysis of the alcohol produced acetaldehyde. Name
Name the organic organic compound. trans-2-Methylcyclohexanecarbaldehyde
the ester. Ethyl ester. Ethyl ethanoate When an ethyl acetate i s reduced by LiAlH4 the product is acetaldehyde Cyclic esters are known as lactones The scent of a banana is due to the ester i-pentyl acetate
Derivatives of carboxylic acid. Acid halide, acide anhydride, ester, amide thioester, acyl phosphate
EXAM
Name the organic compound. 3-(Ethylthio)cyclohexanone
The reagent needed to convert a ketone or an aldehyde into an oxime. hydroxylamine An alkyl group is attached to an aromatic ring on reaction with an alkyl What product would you obtain from hydration reaction of 2,4dimethyl-2-pentene? 2,4-dimethyl-2-pentanol by oxymercuration using
chloride, RCl, in the presence of AlCl 3 catalyst, a process called Friedelcalled FriedelCrafts alkylation reaction A compound whose molecular structure rotates polarized light
mercury (II) acetate followed by sodium borohydride What alkyne would you start to prepare the compound by
counterclockwise: is designated as being le voratatory Which of the following characteristics of chirality is not t rue? The chiral
hydroboration/oxidation reaction? C 6 6 H 5C ≡CH
carbon atom is said to be unsaturated The following are ortho-, para- directors except -CN Methyl groups, although it does not possess a pair of non-bonded p In the catalytic hydrogenation of alkyne to produce an alkene, one
electrons are ortho- and para- directing because they undergo a special
should used Lindlar’s used Lindlar’s catalyst
type of resonance. hyperconjugation
Predict whether the substitution reaction undergoes S N1 or S N2. SN1 reaction because the substrate is secondary and benzylic, the nucleophile is weakly basic, and the solvent is protic.
A 15 inclined manometer containing mercury is connected to two taps A and B containing water. Tap B is 4 ft vertically higher than Tap A. Identify whether this is an R or S configuration. S
When the pressure in Tap B is 6 psi, the manometer reads 5 inches a long the inclined tube. Calculate the new manometer reading (in inches) if the pressure in Tap A is increased by 2.0 psi. 20.7 A cylindrical tank 1 ft in diameter discharges through a nozzle
Predict the major product of the sulfonation of toluene.
o-
connected to the base. Find the time needed for the water level in the
toluenesulfonic acid and p-toluenesulfonic acid
tank to drop from 4 ft to 2 ft above the nozzle. The di ameter of the nozzle
What major and minor products would you expect from elimination
is 1 inch and its discharge coefficient may be taken as unity. 30 s
reaction of the alkyl halide? Major: 2,3,5-trimethyl-2-hexene; Minor:
A device for measuring differential pressure is a manometer
2,3,5-trimethyl-3-hexene and 2 -isopropyl-4-methyl-1-pe -isopropyl-4-methyl-1-pentene ntene
A fluid flowing at a rat e of 25 cubic meters per hour in a 60-mm inside diameter pipe has an average velocity in meters/second equals to 2.5 A horizontal annulus is 27 ft. long. The outside radius of the inner cylinder is 0.495 in.; the inside radius of the outer cylinder is 1.1 in. A
How would you synthesize a secondary alcohol? By reduction of a
60% aqueous solution of sucrose is to be pumped though the annulus at
ketone using NaBH 4 or LiAlH 4
20C. At this temperature the fluid density is 80.3 lb/ft 3 and its viscosity
How would you prepare ethyl phenyl ether? Either a or b
is 136.8 lbm/ft-hr. what is the volume rate of flow when the impressed
Claisen rearrangement is specific to allyl aryl ethers
pressure drop is 5.39 psi? 0.11 ft 3 /s
What is the major product formed from the reaction of benzene with
A pitot tube with a U-tube water manometer is attached to a horizontal
isobutyl chloride and AlCl 3? isobutylbenzene
oil pipe of 4 in. inside diameter. If the manometer reading is 15 in.,
The product of the reaction CH 3CH=CH 2 + H2 is CH 3CH 2CH 3
determine the volumetric flow rate, in gpm of oil in the pipe. The pitot
This test determines a primary, secondary, and tertiary alcohols by
reading is placed at the center of the pipe. The oil has a specific gravity
observing the differences in the reaction rates. Lucas rates. Lucas test
of 0.84 and a viscosity of 0.0336 lb/ ft-sec. 77
Which of the following is the most reactive? 2-pentanone
A pump delivers 40 gpm of water with a total head of 40 ft. The efficiency of the pump is 65%. What is its BHP? 0.62
A rectangular duct 4 m x 1.5 m in a cross-section carries conditioned
If the speed of a centrifugal pump is doubled, the energy requirement
air. Its hydraulic diameter is 2.18 m
becomes approximately 8 times the original energy requirement.
A right angled triangular weir is used to measure the flow rate of water
In a certain chemical plant, the carbonate solution used in the absorption
flowing in an open channel. If the height of the water in the weir is 7.8
tower is pumped continuously from the bottom of the lye storage tank
inches, the flow rate of water is 380 gal/min.
through a standard 4” pipe and then through sprays head at the top of
A rotameter having a stainless float (sp. gr = 8.0) is calibrated to handle
the scrubber. Calculate the efficiency of the pump. 44%
3
a maximum flow of 3.0 m /min of water. What is the maximum flow
In a high pressure piping systems where joints are regularly broken, for
rate of CCl 4 can it handle in m 3/min? 2.3
maintenance, flanged maintenance, flanged joints joints are used.
A sharp edged orifice meter is to be fabricated to measure water flowing
In a reciprocating pump, the ratio of the quantity of liquid actually
at a rate no to exceed 1,200 cu.ft per hour, with a differential head of 30
pumped to that which corresponds to the piston displacement is called
in. Hg. What orifice diameter in inches is required if D 2/D1 is made 1/5?
volumetric efficiency
1.5
Machine which need electricity to run are motors
A water storage tank supplies water into a factory. Water is supplied to
Mass velocity is the independent of temperature and pressure when the
the tank through a booster pump installed in the water line. The
flow is steady is steady and the cross-section is unchaged unchaged
theoretical pump horsepower is 3.25 hp. What is the monthly operating
Natural gas at 70F is flowing at a steady mass rate through a steel pipe
cost of the pump, if electri c power cost on the average is Php3.73/kWh.
with an inside diameter of 12 inches. Absolute pressure drops from 30
The pump is 65% effici ent and operates for 12 hours a day. Php5000
to 15 atm in 400 miles of horizontal pipe. M = 17, μ = 0.01 cP. The
Air is flowing at a constant mass rate through a horizontally arranged
volumetric flow rate per hour at 70 F and normal barometric pressure is
pipe heater and heated from 70F to 170 F. The pressure is normal at
520,000 ft 3
the inlet and the outlet pressure dropped by 1 inch H 2O. the average air
Newton’s law of viscosity relates shear relates shear stress and velocity.
velocity at the inlet is 20 ft/s.
Oil with a viscosity of 30 cP and a density of 60 lb/ft 3 flows through a
Air is to be delivered at a rate of 200 cfm and a pressure of 10 kPa. The appropriate equipment to use is blower An axial flow pump operating at a speed of 880 rpm can supply water at a rate of 3000 gpm. The maximum head that this pump can deliver in feet of water is 36 Assuming that C p = 0.24 and perfect gas, the net heat input is 24 BTU/lbm At a given flow rate through an orifice meter the differential pressure across the orifice will increase when the orifice flow area is decreased At low Reynolds number viscous forces control and inertial forces are unimportant Calculate the radius of the c apillary tube in mm, such that it is a flow of a viscous fluid. Kinematic viscosity = 0.000043 m 2/s, length of tube = 50.2 cm, mass flow rate = 0.003 kg/s, density of fluid = 955 kg/m 3, pressure drop = 4.77 atm. 0.75 Cavitation occurs in a centrifugal pump when suction when suction is lost. Dimension of kinematic viscosity is L is L2T -1. Four-inch (4 inch.) Sch. 40 steel pipes are to be used to transport high pressure steam. The pipe joints are to be butt-welded. The safe working working fiber stress for butt-welded pipes is 457.1 kg/cm 2. Calculate the maximum steam pressure, in kg/cm 2 the pipes can handle. 18.3
½ inch inside diameter pipe. Determine the velocity in ft/s below which flow will be laminar. 16.90 Steam flows at a steady through a converging insulated nozzle, 25 cm long and with an inlet diameter of 5 cm at the nozzle entrance, the temperature and pressure are 325 C and 700 kPa, and velocity is 30m/s. At the nozzle exit, the steam temperature and pressure are 240 C and 350kPa. What is the velocity of the steam at the nozzle exit? 578 m/s The absolute pressure exerted by water 2 m below the surface of a swimming pool is 120 kPa. kPa. The absolute pressure of water one meter below t he surface of a lake is 105 Pa. Pa. The bursting pressure of a pipe is directly proportional to its schedule number The differential height between two points where a fluid has to be transferred is the potential the potential head The dimensionless number that characterizes the flow of fluids in a conduit is Reynolds is Reynolds number The higher the BWG rating of a tube is, the lower is the strength The inside surface of the a pipe has no effect on the friction factor when the flow is streamline is streamline
The power requirement of a 4-stage compressor (in kW) in order to
What will be the rated capacity (in gpm) of a 4-1/2 inch impeller
supply air at 25 C at a rate of 500 cu m per hour at a total discharge
centrifugal pump operating at a speed of 3450 rpm capable of generating
pressure of 200 psig is 63.0 if 63.0 if the efficiency of the compressor is 66%.
a head of 40 ft of water? 248
The power requirement of a fan in kW in order to supply air at a rate of
When a fluid flows through a reducer in a piping system, the velocity at
3
500 m /hr at a total discharge pressure of 05 psia is 0.46 kW.
the outlet end is more than the than the velocity at the inlet.
The pressure after the pump in a 6-inch inside diameter smooth pipe
When the ID of the pipe through which a fluid flows is doubled, the
conducting water is 20 psia. The water is discharged at an open tank 100
pressure loss due to friction per unit length of pipe and for the same
ft from the pump. Calculate the rate of discharge of water in ft 3/s 3.58
volumetric flow rate is changed by approximately a factor of 1/32
The pressure drop in a pipeline changes by a factor of 4 when the
When the impeller speed of an ideal centrifugal pump is doubled, the
velocity of the flowing fluid is doubled.
volumetric flow rate of the discharge is increased by a factor of 2.0
The prime mover of a jet pump is a/an fluid a/an fluid momentum
When the movement of a gas vapor is effected at a low pressure say, up
The required NPSH of a pump is specified to be 8 ft. Determine the
to 0.1 kg/cm 2, the equipment used is a blower
allowable vertical distance above (or below) the pump axis from a
When two bodies lost the same amount of weight when immersed in a
vented surface of water (25 C) in a supply tank if suction side friction
fluid, it means that the two bodies have the same volume.
losses are equivalent to 3.8 ft. 16 ft
When two centrifugal pumps are connected in series, the discharge
The resistance of a layer of fluid to flow over the next layer ismeasured
changes by a factor of 1.
by viscosity
When two reciprocating pumps are connected in parallel, the volumetric
The schedule number of the pipe is an indicator of the pipe’s thickness
capacity of the system changes by a factor of 2
The weight rate of floe of a fluid stream per unit of cross section
Which of the following is not true? The power loss due to friction in a
perpendicular to the direction of flow is the mean mass velocity of the
venturi meter is greater than in an orifice meter.
stream Turbulent flow generally occurs for cases i nvolving none of these Two centrifugal pumps, a 5-in delivering 129 gpm and a 4-1/2 in delivering 140 gpm are connected in parallel. If the pump characteristics of both represented by Fig. 10-38 Perry 8/ed, determine the overall
The material passing one screening surface and retained on a subsequent
efficiency of the pump set. 76%
surface is called intermediate material.
Water at 20C enters an inclined 1-inch ID pipe where the upstream
The minimum clear space between the edges of the opening in the
point is at 10 psig. The downstream point is ½ inch ID and 40 ft below
screening surface and is usually given in inches or millimeters. aperture
the upstream point where the water discharges at 30 gpm to the
The screen used in making size separation smaller than 4-mesh and
atmosphere. What is the friction in ft of water? 28.1
larger than 48-mesh. vibrating screen
Water at 60F is flowing through a 3-inch inside diameter smooth
When the object is to recover an oversize product from the screen,
horizontal pipe. If the Reynolds number is 353,000, calculate the ratio
efficiency may be expressed as ratio of the amount of oversize obtained
of maximum velocity to average velocity. 1.22
to the amount of true oversize.
Water at 80F flows at 10 ft. per second through a 6-inch Sch. 40 steel
The wire diameter of a 14-mesh screen (Tyler Standard) is 0.025 in.
pipe with length of 1000 ft. ft. the Reynolds number is 500,000
Box-like machines, either round or square with a series of screen clothes
What is the differential reading in pitot tube inserted in an 8-in nominal
nested atop one another. Gyratory screen
pipe carrying 1600 1600 gpm of water? Assume Assume mercury to be the fluid in the
The removal of a small amount of oversize from a feed which are
pitot tube. 2.10 in Hg
predominantly fines is called scalping. called scalping.
What is the entrance length in a 2-inch Sch. 40 pipe if the Reynolds
Removal of free water from a solids-water mixture and is generally
number is 1800? 17 ft
limited to 4 mesh and above. Dewatering above. Dewatering
What type of pump would you recommend if the capacity is 5000
Making a size separation smaller than 48-mesh is called ultrafine
gal/min at a head of 15 ft of water? Axial water? Axial flow pump
separation. Another name for revolving screen is trommel screen.
The mesh number of a screen denotes the number of openings per linear
the assumption that all particles in a single fraction are e qual in size is
inch of screen.
not needed.
Materials which remain on a screen surface are called oversize.
Increasing the capacity of a screen decreases the screen effectiveness.
The wire diameter of a 10-mesh screen whose aperture is 0.065 in is
The screen efficiency is none of these.
0.035 in.
As the particle size is reduced screening becomes more progressively
It is desired to separate a mixture of sugar crystals into two fractions, a
more difficult.
coarse fraction retained on an 8-mesh screen, and a fine fracti on passing
A screen is said to be blinded when the screen is plugged with solid
through it. Feed=0.46,coarse=0.88,fine=0.32. the overall effectiveness
particles
is 45%.
Size measurement of ultrafine particles can be best expressed in terms
(15-16) Limestone is crushed by six units operating in parallel and the
of surface of surface area per unit mass.
products separated by six 35-mesh. effective dimension=6ft by 20ft,
Trommels separate a mixture of particles depending on their size. their size.
50tons/hour.
Screen capacity is expressed in terms of tons/h-ft 2
The efficiency of screen operation is 52.8%. The capacity of each screen in lb/24 hour per sq. ft is 5750. 5750 . (17-18) 1800 lbs of dolomite per hour is produced by crushing and then screening through a 14-mesh screen. The total load to the crusher is 6320 lbs/hour
MRII 2nd EDITION
The effectiveness of the screen 62.5% Granular feldspar is produced by beneficiation of high alumina river sand. After screening, drying and magnetic separation, the recovery is only 21%. The MT of river sand with 10% moisture that would have to
A 6,000 lb of a material., Screen analysis shows a surface area of product of 500 sq ft. The Rittinger number of the material i s 163 sq in. The total powr to be delivered to the set of equipment is. 38.4hp
be beneficiated is 12.2 MT. (20-22) Fine silica is fed at 1500 lbs/hour to a double-deck vibrating screen combination to obtain a 48/65 mesh (Tyler) product. The effectiveness of the screening equipment is 48.7% If the screens measure 5ft x 8ft eac h, the capacity in MT/day-ft 2-mm of the 65 mesh screen. 0.901 The capacity in MT/day-ft2-mm on the basis of the actual performance of the 48 mesh screen. 1.09 If the percentage of particles larger that the screen opening in the feed, product, and undersize are 36%, 89% and 3% respectively, the
A fluid energy mill is used for. Ultragrinding A material is crushed in a Blake Jaw Crusher and the average size of the particles reduced from 50 mm to 10 mm. The consumption of energy needed to crush the same material of an average size 25 mm assuming Kick’s Law applies is. 8.88kW/(kg/s) Based on Bond’s Crushing Law, the power required to crush a certain material will change by ___ % if the diameter of the product is made smaller by 50%. 41% Bond Crushing Law. Calls for relatively less energy for the smaller product particle than does the Rittinger Law
effectiveness of the screen is 88.5
Cement clinker is commonly reduced to fine size using a. Ball a. Ball Mill
The Tyler Standard screen series is characterized by twice the area ratio
Crushing efficiency is the ratio of. Surface energy created by the crushing to the energy absorbed by the solid
between successive screens. The ratio of the clear opening corresponding to a mesh size in the Tyler Standard screen series to that of the next screen is sqrt(2). The clear opening of a 200-mesh screen in the Tyler Standard screen series is 0.0074 cm The ratio of the area of the opening in one screen (Tyler Series) to the opening of the next smaller screen is none of these. The Cumulative Screen Analysis for determining the surface area of particles is more precise than the differential screen analysis analysis because of
Defined as the efficiency of technical grinding compared with laboratory crushing experiments. Practical experiments. Practical Energy Efficiency Equivalent diameter of a particle is the diameter of the sphere having the same. Ratio same. Ratio of surface to volume as the actual volume For coarse reduction of hard solids, use. Compression Hardness of a mineral is a criterion of its resistance to crushing. Which of the ff is a hard material. sapphire material. sapphire Hp required by the ball mill when loaded is. 5.4hp
If 20% of pulverized limestone with a work index of 12.74 kWh ton is retained by a 150 mesh screen from original 35 mesh, the energy required in kW to process 1 ton/hr is.6.25 is. 6.25 In comminution, the energy requirement is determined theoretically by. The initial and final sizes of the particles In crushing a certain ore, the feed is.. 80% is less than 50.8mm in size and the product size is 80% less than 6.35mm. The power required is 89.5 kW. Based on Bond eqn, power required using the same feed so that 80% is less than 3.18 mm is. 146.7kW Problems 12-14. A ball mill is to grind 250 tons/day of calcite having a specific surface of 90.34 sq cm/g. Energy effectiveness is 7.5%. Given table. The specific surface of the product is. 179.2sq cm/g
A composite three layered wall is formed of a 0.5cm thick aluminum plate, a 0.25cm thick layer layer of sheet asbestos. Given Given a table for values values of temp and k. Determine the heat flow per unit area. 1085 W/m2 A composite wall consists of 2” corkboard, 6” concrete and 3” wood. What are the temperatures between the cork and concrete and between the concrete and wood? 62.7F, wood? 62.7F, 64.9F A composite wall consists of W1(outer layer) and W2 (inner). W1 and W2 are both 5 in thick. The temp of the outer layer is 500F while that of the inner is 1500F. Find qtotal in BTU/ hr ft2. 218 A furnace wall is constructed of firebrick 6 in thick. If the mean thermal conductivity under these condition is 0.17 BTU/h ft F. What is the rate of heat loss through 10 sqft of wall surface? 3825 BTU/hr
Rittinger’s Crushing Law states that.Work that. Work required in crushing is proportional to the new surface surface created
A pipe with an outside diameter of 2.5 inch is insulated with a 2 inch layer of asbestos followed by a layer of cork 1.5 inch thick. Calculate the heat lost per 100 ft of insulated pipe. 2847.4 BTU/hr
Shape factors are important in characterizing.. The specific surface in sq cm/g for quartz with diameter of 2 in, density of 165 lb/cu ft and a shape factor of 20 is. 4.47
A reaction mixture having a Cp = 2.85kJ/kg K flowing at a rate of 7260 kg/hr. The overall Uo is 653 W/m2 K. Calculate the area assuming flow is countercurrent. 5.43m2
Size reduction is important since. It It prepares raw materials of the desired sizes prior to processing
A semi-infinite solid in heat conduction is one where. Only the conduction on one side affects the temp distribution
Soft and non-abrasive materials can be made into fines by. Attrition by. Attrition
A theoretical body where the absorptivity and emissivity are. Wavelength over the spectral region of t he irradiation. Gray Body
Sphericity for a cylinder whose length equal its diameter is. 0.87 States that energy required for crushing is proportional to the new surface area. Rittinger’s area. Rittinger’s Law The average diameter of sphalerite is 1000 microns, the ration of specific surfaces is. 4 The critical speed of a ball mill with 12 in diameter, grinding balls diameter of ½ in. 80 The operating speed of a ball mill should be. Less Less than the critical critical speed The term applied to all ways in which particles of solids are cut or broken into smaller pieces. size pieces. size reduction Theoretical horse power requirement to grind the calcite. 1.38hp Wet grinding in revolving mill. Increases capacity compared to dry grinding Work index is defined as.. 80% of product passes a 100 microns s creen. What is the work index of gypsum rock? 6.73 Work index is defined as. Gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes a 100 micron screen
A 2-4 shell and tube heat exchanger means that there are. 2 baffles and 4 tubes A 6 in thick wall is 12 ft high and 16 ft long. One face is at 1500F and the other at 300F. The total heat loss in BTU/hr is. 69,120 BTU/hr
A thick walled copper cylinder has an inside radius of 1 cm and outside radius of 1.8cm. Assume k varies linearly with temperature. Determine the heat loss per unit length. 40 kW Air flowing inside the annular space of a double pipe heat exchanger is being heated by steam inside the inner pipe. For t his case, the U in the heat transfer equation should be based on. The outside area of the inner pipe Air is cooled in a double pipe counter current heat exchanger from 120 F to 100 F with water entering at 60 F and leaving 75 F. The largest temperature range in the heat exchanger is. 20F An ideal surface that absorbs all incident radiation, regardless of wavelength and direction and is also considered to be a perfect emitter is referred to as a. Black a. Black Body An industrial furnace wall is constructed of 0.7ft thick fireclay having k = 0.6BTU/hrft F. Outer surface with a 0.1 ft thick layer of insulating material. Calculate the steady heat transfer per square foot. 464 BTU/hr ft2 Assuming Reynold’s Number analogy applies, estimate the heat transfer coefficient for water flowing inside a 2 in ID smooth horizontal pipe at a velocity of 4 fps and andave temp of 78F. 2240 Determine the steady state heat transfer per unit unit area through a in thick homogenous slab with its two faces maintained at uniform temp of 100 and 70. The thermal conductivity of the material is 0.11 BTU/hrft F. 26.40 BTU/hr ft2 For a furnace constructed with 0.7ft thick of fireclay brick having k – 0.6 BTU/hrft F. How thick must the insulator be to maintain a maximum allowable heat transfer rate of 300 BTU/hrft2? 0.20ft
If a man touches two metals which were kept together at room temperature, why would one metal feel colder than the other? One has a high thermal conductivity If the thermal conductivity of the fluid increases, the heat transfer coefficient will. Increase will. Increase If the viscosity of the fluid will increase, the heat transfer coefficient i n a turbulent flow system. Decrease system. Decrease In a 1 shell pass 1 tube pass heat exchanger with horizontal tubes 25 mm external diameter and 22 mm internal. Assume atmospheric pressure. What will be the total length of the tubing required? 526m In a fluid, if the currents are set in motion by the action of a mechanical device, and the flow is independent of density gradients, the phenomenon is called. Forced called. Forced Convection In boiling the stage when the rate of bubble formation increases so that the velocity of circulation increases and the heat flux also increase is referred to as. Nucleate as. Nucleate Boiling In heat transfer by conduction, due to symmetry the heat flow at a point is perpendicular to the isothermal surface through the point. This mode of conduction is characteristic of. Isotropic of. Isotropic Solids In using the design equation of heat transfer. For a system where air is flowing inside a pipe while being heated by condensing steam outside the pipe, the proper U and A to be used is. Based on the inside area It is a method of developing the design for a heat exchanger wherein the engineer assures the existence of an exchanger and makes calculation to determine if the heat exchanger would handle the process requirements.. Rating Rating a heat exchanger The amount of radiation emitted in all directions and over all wavelengths by a perfect emitter is proportional to the fourth power of the absolute temp of the emitter. This is the statement of. Stefan Boltzman Law The driving force in heat transfer is. Temperature gradient The equation q/A = -k dT/dx is called. Fourier’s called. Fourier’s Law The heat transferred radially across an insulated pipe per unit area. Decreases from pipe to the thermal conductivity conductivity The LMTD for the heat exchanger of Prob 42 is. 42.5F The measure of the relative effectiveness of momentum and energy transport by diffusion in the velocity and thermal boundary layers is given by. Prandtl Prandtl Number The property of the solid that provides a measure of the rate of heat transfer relative to the energy storage is referred to as. Thermal Diffusivity The range of wavelengths of electromagnetic waves that is associated with thermal radiation is from. 0.1 to 100 micrometer The ratio of the emissive power of a body. Same for all radiating bodies in a confined.. This is a statement of. Kirchoff’s Kirchoff’s Law The ration of the internal thermal resistance of a solid to the boundary layer thermal resistance is described by. Biot by. Biot Number
The smallest temp approach in the heat exchanger of Prob 42 is. 40F The spectral distribution of a perfect emitter has a maximum and that the corresponding wavelength depends on temperature. The maximum spectral emissive power is displaced to shorter wavelengths with increasing temperature. These statements refer to. Wien’s Law The term hD/k is known as. Nusselt as. Nusselt Number The transfer of heat from a point to another within a fluid, or between a fluid and a solid or another fluid, by the movement or mixing of the fluids involves. Convection The triangular center to center distance of a bank of 2 in OD tubes in a furnace is 6 inches. Estimate the total view factor. 0.72 The view factor F21 of a sphere of diameter D inside a cubical box if L = D. 0.524 Thermal lumped analysis may be applied if. The conductive resistance is very small compared with the convective resistance Two parallel infinite walls at diff temperatures are radiating energy to each other. The heat transferred by radiation between the two walls. Decreases Water is flowing inside a ¾ inch 14 BWG condenser tube (hi = 20 kW/m2 C) and saturated steam (ho = 35) condensing outside. If k of t he tube is 120 the value of Uo is. 10.8 When water inside a beaker is being heated over a hot plate, the mechanism of heat transfer through the water is considered to be. Natural Convection Which among the gases listed is transparent to gas radiation. Oxygen
All of the following is used as a hygroscopic material in desiccators EXCEPT. H2SO4 EXCEPT. H2SO4 Chemicals which are tested by the manufacturers showing the actual percentages of impurities impurities and labeled on the containers are called. All called. All of these Platinum crucibles can be used for the ff processes without significant loss EXCEPT. Heating EXCEPT. Heating with sulfides What grade of water as defined by the British Standard is suitable for the determination of trace quantities which can be prepared by the distillation of deionized water? Grade 2 The following describes colloidal suspensions formed during precipitation except. They settle readily from a given solution Which of the ff does not describe the correct way to wash precipitates? For very soluble precipitates, ionic salts containing common ion must be added to the washing liquid Analytical methods classified as micro analyses use sample mass ranging from.1-10mg from. 1-10mg It is expressed as the volume of a solution chemically equivalent to a mass of a solid reagent. Titer Process by which an agglomerated colloid return to its dispersed state during washing due to leaching of electrolyte responsible for its coagulation. Peptization coagulation. Peptization Which of the ff statements is not correct? In correct? In general, alkaline buffering capacity is maximum over a pH range of pKb +-1
The conjugate base of H2PO4 is. HPO4 is. HPO4 In the standardization of an acid solution with primary standard sodium carbonate, why is it necessary to boil the solution before completing the titration? All titration? All of these
Which of the ff situations will result in a solution with the lowest value of pH? A pH? A high concentration of an acid acid with a high value of Ka. What effect will the a ddition of pure water to a water solution of an acid have on the pH of this acid solution? The pH level will increase
Which of the ff aqueous solutions of the same concentration will have the largest pH value at 25? NH3 25? NH3
Which of the ff will form a basic solution when dissolved in water? The salt of a weak acid and a strong base
Which of the ff solutions at 25C will have the lowest pH value? 0.01 M NH4Cl
A 750.25 gram alloy of nickel was dissolved and treated to remove impurities.. Determine the % Ni in the alloy. 10.53%
Which of the ff acid base pairs will result in the formation of a buffer solution when titration is done before the equivalence point? NH3 point? NH3 - HBr
What proportion by weight of Na2C2O4 to that of KHCO4 etc that must be mixed in a solution so that the normality of the resulting solution as a reducing agent is three times the normality as an acid? 0.65 acid? 0.65
What is the best basis for choosing the right indicator for a given acid base titration from among the following? following? pH pH at equivalence point In the titration of a weak acid with a strong base, which of t he following is the best indicator to be used? Phenolphthalein used? Phenolphthalein Process of determining the nitrogen content of organic materials by mixing the sample with powdered copper oxide and ignited to a combustion tube giving CO2, H2O H2O N2 and small amounts of nitrogen nitrogen oxides. Dumas oxides. Dumas Method A 500 mg sample of each mi xture was analyzed for its alkaline c ontent using 0.1025 M HCl via double indicator method. Table is given. Which of the following mixture contains NaHCO3? Mixtures 1 and 2 In the analysis of nitrogen using Kjeldahl Method, which of the ff is added to decompose organic matrices present in the sample? HgO sample? HgO Which of the ff is not used as primary standard for the standardization of alkali solutions? HgO solutions? HgO Which of the ff is not a correct analytical method-titrant pair? Volhard AgNO3 In Volhard Method, why is it necessary to carry out titration in acidic solution? To prevent precipitation of iron as hydrated oxide
What volume of water must be added to concentrated HCL solution to prepare 100 mL 0.955 0.955 M HCl solution?92.1mL solution? 92.1mL A 20% wt/wt aqueous soln of NaCl at 25C has a density of 1.145 g/mL. Express the amount of solute in this solution as %wt/vol. 23 %wt/vol. 23 Molarity.1.96 Molarity.1.96 Molality.6.84 Molality.6.84 A 1.5176 g sample of CaCO3 was dissolved in acidic solution. What is the percentage of CaO in the sample?23.8% sample? 23.8% A mixture containing FeCl3 and AlCl3 only weighs 750.8 mg. Calculate the percentage Al in the sample.41.2% sample. 41.2% What is the extent of i onization of the second proton of 0.5M H2SO4 at 25C?2% 25C?2% What weight of Mn ore should be taken si that the percentage of MnO2 in the ore would be twice the mass of Mn3O4 precipitate obtained in milligram?57 milligram?57 mg
With the presence of Pb2+ ion, what is the color of the precipitate? Yellow
What volume of 0.1025M HCl must be added to 15.64mL of 0.0956 M NH3 to produce a solution of of pH = 9?9.3 9? 9.3 mL Approximately how many grams of NH4Cl should be dissolved in a liter of 0.125 F NH3 to reduce the concentration of hydroxide ions to onethousandth of its original value?79.1g value?79.1g
A solution has a pH of 6 will give ___ color if added with a drop of methyl red. Yellow
Calculate the molarity of NaOH solution if 12.25 mL was used to titrate 0.2615 gram of primary standard KHP.0.1045 KHP. 0.1045
Which of the ff ions is best titrated with EDTA at mi nimum pH less than 7? Fe3+ 7? Fe3+
In standardizing a solution of NaOH against 1.431 grams KHP. 35.5mL alkali. What is the molarity of the NaOH solution?0.2598M solution? 0.2598M
Which of the ff statements is true? Ca-EDTA complex is more stable than Mg-EDTA complex.
A 0.2055g sample of calcite is treated with 27.18 mL of 0.0712 N HCl. Calculate the percentage purity of calcite in terms of % wt/wt CaCO3. 35.6%
Commonly, the analyte in a sample is present in two different oxidation states. One of the metallic reductors is zinc soaked in a dilute solution of mercuric chloride. This reductor i s known as. Jones as. Jones Reductor Which of the ff is false about iodine as an oxiding agent in titration? Iodine is very soluble in water and losses losses are minimal All of the following is used in redox titrations except. Iodide except. Iodide Which of the ff metal is not reduced by Walden reductor? Cr Which of the ff is used as pre-oxidant? All pre-oxidant? All of these
Calculate the purity of the sample containing NaHCO3 only. 10.64% What is the %wt of NaOH for the sample containing a mixture of NaOH Na2CO3? 1.82% A 7.279 gram sample of meat was analyzed for its nitrogen content using Kjeldahl Method. The resulting solution was titrated with 37.25mL of 0.3122M HCl using mixed indicator. Determine the % protein in the sample using 6.25 as factor for meat products. 13.98%
A 1.5 gram sample of impure aluminum chloride was dissolved in water and treated with 45.32mL of 0.1000M AgNO3 using K2CrO4 as indicator. Express the analysis in %AlCl3. 13.43% A mixture of LiBr and BaBr2 weighing 800 mg is treated with 50 mL of 0.1879 M AgNO3. What is the percentage of BaBr2 in the sample? 67.95% A 500 mg sample containing NaCN required 23.5 mL of 0.1255 M AgNO3 to obtain a permanent faint turbidity. Express the result of this analysis as % CN. 30.67% An EDTA solution was prepared by dissolving the disodium salt in 1L of water. The standard solution was used to determine the hardness of a 2L sample of mineral water which required 35.7mL of EDTA solution. Express the analysis in terms of ppm CaCO3. 316ppm The 300 mg sample of impure Na2SO4 was dissolved in sufficient water and the sulfate was precipitated by the addition of 35 mL of 0.1022 M BaCl2. Calculate the purity of the sample. 90% At pH = 7 and a pressure of 1 bar, the potential for the half reaction 2H + 2e = H2 is. -0.414V What is the molality of a KMnO4 solution standardized against 1.356 gram Na2C2O4 requiring 25.1mL of the solution in acidic medium? 0.161M A sample of iron ore weighing 385.6mg was dissolved in acid and passed through a Jones reductor. Calculate %Fe3O4 i n the ore sample. 90.30% A sample of pyrolusite weighing 0.24 gram was treat ed with excess KI. The iodine liberated required 46.24 mL of 0.1105M Na2SO3 solution. Calculate the % MnO2 in the sample. 92.54% A 10 gram sample of cooked ham was pureed with 200mL of water, filtered and the resulting solution containing dissolved potassium nitrite was acidified. Calculate the amount of nitrite. 900 A 100 mL water sample was analyzed by Winkler Method. If 7.52 mL of 0.0124M Na2S2O3 was used for titration, determine the ppm of O2 in the water sample. 7.5 A 500 mg sample of a solution containing cobalt and nickel was dissolved and diluted to 50 mL. Given table. Calc ulate the concentration of Co in the solution in ppm. 2343ppm What is the concentration of the Ag+ ion in a saturated solution of AgCl? Ksp = 1.7x-10. 1.3x10-5 M A 0.2M solution of weak acid HA i s 0.6% ionized. What is the value of Ka for this acid? 7.2x10-6 Calculate the pH of an aqueous buffer solution which contains 0.10mol/L NH3 and 0.2 mol/L NH4Cl. 9 100 mL of NaOH solution is added to 150 mL of 0.2M HAc solution. Calculate the final H+ ion concentration. 3.7x10-5M A 5.82 gram silver is dissolved in nitric acid. When sodium chloride is added to the solution, all the silver is precipitated as AgCl. Determine the % silver in the coin. 93.1%
What volume of a 1M solution HCl is required to neutralize 80 mL of 0.5M NaOH? 40 mL A 1 gram sample of a mixture contains only NaCl and KCl gave a precipitate of AgCl which which weighed 2 g. What is the %K in the mixture? 45% In standardizing a solution of HCl, it is found that 47.26 mL of the acid are equivalent to 1,216 g of pure Na2CO3. What is the normality of the acid? 0.4855N What is the pH of a solution of 0.0500 M NH3? Kb for NH3= 1.8E-5. 11 A mixture containing only KCl and NaBr is analyzed by the Mohr method. A blank titration requires 0.71mL of titrant to reach the same end point. Report the %w/w KCl in the sample. 82.6% The concentration of a solution of EDTA was determined by standardizing against a solution of Ca2+ prepared using a primary standard of CaCO3. After adding calmagite as an indicator, the solution was titrated with the EDTA, requiring 42.63mL to reach the end point. Molar concentration of EDTA in the titrant. 9.53E-3 A 0.917 g sample of canned tuna was analyzed by modified Kjeldahl method. Calculate the percentage of nitrogen in the sample. 3.93% A 0.7535 g sample of wheat flour was analysed by the Kjeldahl method. Calculate mass of nitrogen in the sample in grams. Given that proteins are 5.7% nitrogen by mass, calculate the percentage protein in the flour. 39.2% The concentration of LiOH is 0.50M. If 25mL of LiOH is needed to titrate 40 mL of HNO3 what is the concentration of the acid? 0.3125M What is the pH of a solution composed of 0.20M NH3 and 0.15M NH4Cl? 9.38
A 50mL of 0.050M HCl is to be titrated with 0.10M NaOH. Before the addition of any titrant what is the pH of the solution? 1.3 After the addition of 10 ml of NaOH, what is the new pH of the solution? 1.6 After the addition of 30 ml of NaOH, what is the new pH of the solution? 11.8 How many grams of solid KF (MW = 58.1 g/mol) should be added to 1.00 L of 0.250 M HF to make a buffer of pH = 3.143? Ka for HF = 7.20 x 10-4. 14.5g
It is defined as the fraction 1/273.16 of the temperature of the triple point of water. Kelvin The amount of heat absorbed when CO 2 gas reacts with a solid CaO to form solid CaCO3 is measured in a bomb calorimeter. The data obtained give a direct measure of. ΔU of. ΔU Heat required to raise the temperature of one p ound mass of a substance by 1ºF. BTU 1ºF. BTU Which of the following physical quantities is not conserved in a given process? Entropy process? Entropy
During adiabatic expansion of an ideal gas, work is done by the system and its internal energy decreases All of the following have standard enthalpy of formation values equal to zero at 25ºC except. Na except. Na The work that may be performed on a system ___ when the opposing pressure differs differs only infinitesimall infinitesimally y in magnitude magnitude from the internal internal pressure pressure of the gas itself. Minimum itself. Minimum Which of the following statements statements is true?(a)work or mechanical energy can spontaneously be converted completely to heat or thermal energy.(b)thermal energy with some effort, can only be partially converted to mechanical energy.(c)For a closed system operating adiabatically, adiabatically, work is obtained from the direct conversion of internal energy of the fluid to work. (d) all of these A Carnot cycle operates on the following processes. two isothermal and two isentropic processes The natural flow of heat is described in the statement of Clausius Which of the following is true about the Otto cycle? The thermal efficiency is greatly influenced by the compression ratio and the specific heat ratio of the working fluid. Which of the following statements is false in terms of increasing the efficiency of the ideal Rankine cycle? Increasing the boiler pressure will increase the efficiency and reduces the moisture content of the steam. A sample of an ideal gas is allowed to escape reversibly and isothermally into a vacuum. Which statement is correct? W=Q=ΔU=0 The ratio of coefficient of thermal expansion, α and isothermal compressibility, compressibility, қ Tis equivalent to. ( T P/ T) )V Which of the following reaction will result to an increase in entropy? I 2(s)↔ 2(s)↔ I 2(l) 2(l) If a forward reaction is observed to be spontaneous, which of the following is possible if its reverse reaction is spontaneous at high temperature? ΔH( temperature? ΔH( -) -) and ΔS( -) -) In a Rankine cycle, the condition of steam leaving the turbine could be any one of the following except. saturated except. saturated liquid liquid (18)A (18)A refrigerant whose molecular formula is CBrF 2CBrF2 is labeled as R114B2 Calculate the Joule-Thomson Joule- Thomson coefficient, μ (K -MPa -MPa-1) of a -1 -1 chlorofluorocarbon (Cp=0.6923 kJ-kg -K ) using the following data at 25ºC. 28.8 A 400 mg sample of liquid ethanol was burned in a bomb calorimeter resulting to a rise of 2.86ºC. Calculate the molar heat of combustion of ethanol at constant pressure… -1367 kJ-mol -1 Refer to the following data for two moles of nitrogen gas which obey the van der Waals equation of state: T 1= 250K, V1= 5L, T2= 100K, Cv= 28 J-mol-1K -1, a= 0.1408, b= 3.913x10 -5. What is the change in the internal energy (kJ) accompanying the reversible expansion of this gas to a final volume of 80L? -8.3. If the expansion was adiabatic, what is the final volume (L) of the gas? 107.8 Calculate the work (J) done by a sample of 0.10 mole Ne gas that expands isothermally isothermally from 0.6L to 1.2L at 0ºC according to the following conditions: conditions: against a constant external pressure of 0.9 atm. 55. 55. against a variable pressure which varies with volume according to the expression PV n=k and with the
given data: 7 re re versibly assuming gas is ideal. 157. reversibly assuming gas obeys van der Waals equation of state(a=0.86). 151 Twenty grams of oxygen gas at 25ºC expands adiabatically and reversibly from an initial pressure of 0.1 atm to 3 atm. Final temperature (ºC) of the gas. -85. -85. If expansion was done against a constant external pressure of 1atm, calculate the work (J) done by the gas. 1428 Steam at 300ºC and 2MPa enters a nozzle with inlet diameter of 5cm at a steady state flow rate og 0.5 kg-sec -1. If heat is lost is lost at a rate of 10kJ/s and steam leaves the nozzle at 200ºC and 1.4 MPa, determine the outlet diameter of the nozzle. 1.2cm It is proposed to warm a collector plate with solar energy. The collected energy is then transferred as heat to a fluid in a heat engine which in turn rejects heat to the atmosphere. atmosphere. If 200BTU/hr-ft 2 of energy can be collected when the plate is operating at 190ºF... 92ft 2 What is the minimum work (BTU) required to produce 10lbs of ice from water initially at 32ºF ass uming that the surrounding air is at 85ºF… 155 A certain process requires cooling of a brine solution continuously from 70ºF to 30ºF. The atmospheric temperature is 80ºF. There is an available refrigerator with a power requirement of 40kW.Can this refrigera tor…no tor… no Ice cube initially at -5ºC weighs 20g and dropped into an insulated vessel conta8ining 100g of water at 90ºC. What is the final temperature temperature of the water after the ice melted and a constant temperature has been reached? 61.3ºC . What is the entropy change (J/K) accompanying this process? 7.7 Calculate the change in molar Gibbs free energy of liquid water treated as incompressible incompressible fluid when pressure is increased from 1 bar to 2 bar at 298K. 1.8J/mol Steam at 300ºC and 1MPa enters a turbine at a rate of 5kg/s. The turbine is well insulated and operates at steady state. The steam outlet pressure is 0.7 MPa. Using the following data, calculate the following: Calculate the work obtained from the turbine if the process is isentropic. 442kW . If the outlet temperature was measured to be 225ºC at the same outlet pressure, what is the isentropic isentropic efficiency efficiency of the turbine? turbine? 98.5% An ideal Otto cycle has a compression ratio of 10. Air at 100kPa and 25ºC undergoes isentropic compression and 1000kJ/kg of heat was transferred to air at constant volume. Assume air behaves like an ideal gas and its properties remain remain constant constant with C p= 1.005 kJ/kg-K and ϒ=1.4, calculate the following: thermal efficiency, ƞ. 0.60. 0.60. mean effective pressure pressure (kPa). 781 An ideal Diesel engine uses air initially at 20ºC and 90 kPa at the beginning of the compression process. If the compression ratio is 15 and the maximum temperature temperature in the cycle is 2000ºC, determine the:. net work (kJ) produced. 812. 812. mean effective pressure (kPa). 930. 930. cut-off ratio. 2.6 A simple Rankine cycle operates such that the condenser produces saturated saturated water at 70ºC. Water is compressed to 5MPa and heated in the boiler to produce saturated steam. Assume pump and and turbine turbine to operate isentropically. isentropically. Using the following steam table, calculate the following: Quality of steam produced from the turbine. 0.74 Thermal efficiency of the cycle. 0.31. What is the mass flow rate (kg/s) of steam required to produce 500 kW net power using this cycle? 0.65. Is the thermal efficiency of the cycle is 25%, calculate the steam quality leaving the turbine. 0.80 An ideal vapor-compression refrigerant cycle operates between 0.1 MPa and 0.8 MPa uses refrigerant-134a as working fluid. Using the data below, determine the following: Quality of the vapor from the throttling valve. 0.36. COP 3.21. If the throttling valve is replaced by an expansion turbine, calculate the COP of the
cycle4.25. cycle 4.25. Evaluate the expansion coefficient, α for an ideal gas at STP. 3.6610x10-3 /K
Centrifugation
The capacity in cubic meters per hour of a clarifying centrifuge operating under these conditions is 210m3 /h Diameter of the bowl= 600mm Thickness of liquid layer= 75mm Depth of the bowl= 400mm Speed= 1200rpm Specific gravity of liquid= 1.2 Specific gravity of solid= 1.6 Viscosity of liquid= 2cp Cut size of particles= 30μm If a centrifuge is 3ft diameter and rotates at 1000rpm, the speed of laboratory centrifuge of 6 in.diameter be ran if it is to duplicate plant conditions is 2449rpm A centrifuge with a phosphor bronze basket, 380 mm in diameter, is to be run at 67 Hz with a 75 mm layer of liquid of density 1200kg/m 3 in the basket. What thickness of wall is required in the basket? The density of phosphor bronze is 8900kg/m3 and the maximum safe stress for phosphor bronze is 87.6 MN/m2. 15.1mm In a test conducted using a laboratory centrifuge, it was found that the optimum recovery of protein from coconut oil was achieved with an rpm of 2,500. Industrial size centrifuge comes in 3.5, 3.0, 3.5, 4.0, and 5.0 ft diameter with warranty if the centrifuge is operated not over 1000 rpm. For optimum commercial operations, the centrifuge size you will recommend is. 3.0 ft per ft Determine the filtration rate that can be expected from a basket centrifugal filter using the data below: Basket height= 12in Inside basket diam.= 26 in Rotation rate= 2000rpm Material to be filtered: gypsum slurry,α= 2.52x1011/lb;Ɛ= 0.5 Specific gravity of CaSO 4•2H2O = 2.65 Assume that the cake is incompressible, filter medium resistance is negligible and the liquid surface corresponds to the filter cake surface and the thickness of the cake is 1in. 0.60gpm A batch centrifugal filter having a bowl diameter of 750 mm and a bowl height of 450mm is used to filter a suspension having the following properties: Temperature: liquid, water= 25ºC; Porosity of cake= 0 .435 Final thickness of cake= 150mm Specific cake resistance= 9.5x10 10ft/lb Filter medium resistance= 2.6x10 10 per ft Speed of centrifuge=2000 rpm Density of dry solid in cake= 2000kg/m 3 Conc.of solids in feed= 60g/L The final cake is washed with water under such conditions that the radius of the inner surface of the liquid is 200mm. Assuming that the rate of flow of wash water equals the final rate of flow of filtrate, the rate of washing in m3/hr?0.60 /hr?0.60 The capacity of a Sharples centrifuge is estimated to increase/decrease by ___% if its speed is doubled and the cut size of the particles is reduced by 20%. 156%
A centrifuge with a bowl which is 500mm long and has an inside radius of 50.5 mm is to be used to separate crystals from a dilute aqueous mother liquor. The optimum speed of rotation for the centrifuge is 60,000 rpm, and the discharge weir is adjusted so that the depth of liquid at the bowl wall is 38.5 mm. The crystals are approximately spherical and none are smaller that 2x10-6 m in diameter. The maximum volumetric flow rate in m 3/s of the mother liquor that can be processed by this centrifuge if all the crystals have to be removed is 0.054 A centrifuge with a radius of 76.2 mm rotates at a peripheral velocity of 53.34m/s. The centrifugal force developed compared to gravitational force in the bowl centrifuge is 3800g A centrifuge bowl is spinning at a constant speed of 2000 rpm. The radius of bowl in cm needed needed to create a force of 455g is 10.2 For the separation of sugar solution from settled out mud, we use centrifugal filter Moisture can be removed from lubricating oil using tubular centrifuge Which of the following can be most effectively used for clarification of lube oil and printing ink? Sharpless supercentrifuge If the radius of a basket centrifuge is halved and the rpm is doubled, then the centrifugal force is doubled Where the difference in density of the two liquid phases to be separated is very small (as in milk cream separator), the most suitable separator is disc bond centrifuge
Diffusion
The enrichment of ethyl alcohol in the vapor phase from an aqueous ethyl alcohol solution during rectification is an example of equimolalcounterdiffusion The diffusivity of a binary system as given in the equation of Fick’s Law is usually measured relative to the volume-mean velocity of components A and B The molecular diffusion flux of A is 4.0x10 -7 gmoles/s-cm 2 at 298 K and 1 atm. What will be the bulk velocity in cm/s if the diffusion flux relative to a stationary observer is 8.0x10 -7 gmole/s-cm 2 and the mole fraction of A is 0.015? 0.65 The diffusivity of a component A relative to itself, that is D meaning and can be measured
AA. has
a physical
The Reynolds Analogy is applied when the Prandtl Number is unity The molar flux of component A in molecular diffusion is independent of mass transfer area A dimensionless number that represents the ratio of the mass transferred by molecular diffusion to the total mass transferred. (a)Sherwood No. (b)Reynolds No. (c)Schmidt No. (d) None of these The molar diffusion flux of A relative to a stationary plane is a combination of phase of phase drift + molecular molecular diffusion diffusion The Fick’s Law of Diffusion gives the rate of diffusion based on concentration concentration driving force Equimolar counter-diffusion means that the bulk in terms of moles is not moving
For a gas phase diffusion, unicomponent diffusion through gas-liquid interface will likely to occur if one if one component is soluble and the other is not
temperature of the liquid remains constant at 17ºC. Diffusion takes place…1.91 place…1.91 x 10 -5m2 /s
The rate of mass transfer of component A through an interface in a turbulent flow system is less affected by the flow rate of gas and liquid
A sphere of naphthalene having a radius of 2 mm is suspended in a large volume of still air at 318 K and 1 atm. The surface temperature of the naphthalene can be assumed to 318 K. The diffusivity at 318 K and 1 atm is 6.92 X 10-6 m2/s and its vapor pressure at 318 K is 0.555 mm Hg. The rate evaporation of naphthalene in gmole/s is. 4.9 x 10-9
For a binary unicomponent diffusion, the concentration profile of the diffusing component along the diffusion path is logarithmic The transport analogy among mass, heat and momentum transfers is complete when no convective flux or phase drift is involved A wetted-wall column is usually used to determine mass transfer coefficient experimentally experimentally because the mass transfer are can be measured accurately It provides the basis for the quantitative description of the diffusional phenomena of molecules. molecules. Kinetic Kinetic Theory of Gases The method of solute transfer which involves rapid movement of large chunks of fluid in turbulent motion eddy diffusion Ammonia (A) being absorbed from air (B) into water is an example of steady state unicomponent unicomponent diffusion diffusion
The unicomponent mass transfer coefficient is 3.25 x 10 -5kgmole/s-m 2-mole at 300 K and 2 atm. If Y A1=0.26 and YA2=0.01, the equimolal MTC is ___ kgmole/s-m 2-mole. 2.792 x 10 -5 The equivalent equimolal MTC for the above problem in lbmole/hr-ft lbmole/hr-ft 2-atm is 0.0205 Based on the penetration theory, the MTC will increase/decrease by a factor of __ if the contact time of the diffusing phases is tripled. 0.5773 The time it will take to evaporate a 10 mm unknown liquid at 25ºC (density= 40 lb/ft 3, MW = 60) in a 5-m diameter circular tank is ___hr. The vapor pressure at 25ºC is 180 mm Hg, pressure is atmospheric atmospheric and D V=0.0329 ft2/hr. Stagnant air film is 10 mm. 31.6hr
In steady-state equimolalcounterdiffusion, the following are true: N A= N B;N A+N B is zero Process Control
It represents the total mass transferred to mass transferred by molecular diffusion. Sherwood Number The flux of A in unicomponenrt diffusion is different from that of equimolalcounterdiffusio equimolalcounterdiffusion n because of the bulk motion of the phase It is a measure of the diffusive mobility of individual molecules in solution. Diffusion coefficient coefficient The volumetric diffusivity diffusivity of a binary mixture is 0.934 ft 2/hr at 30ºC and 2 atm. The molal diffusivity for a similar mixture is ___lbmole/ft-hr. 4.688x10-
The simplest mode of control which is characteristic of a two-position control commonly utilized in a thermostat for controlling the temperature of heaters, air-conditioners, air-conditioners, refrigerators,etc. refrigerators,etc. on-off control It is a control system in which the control action is independent of the output. Open-loop system An arrangement of physical components connected or related in such a manner as to command, direct or regulate itself or another system. Control system
3
The diffusivity of benzene in air at 0ºC and 1 atm is 0.299ft 2/hr. The diffusivity of benzene in air at 22ºC and 1atm is. 0.089 cm2 /s Ethyl alcohol is diffusing into an alcohol-water solution at 18ºC. The concentration concentration of alcohol in the bulk of the solution is negligible, while that at the surface of the solution is 0.12g/cc. The film thickness is 0.15cm and the diffusivity is 1x10 -5 cm2/s. The mass of alcohol diffusing through 100 ft 2 of interface per hour is. 6 lb The diffusivity of ethyl alcohol in air at 25ºC and 1atm is 0.135cm 2/s. Based on Chen and Othmer diffusivity empirical correlation, the diffusivity at 80ºC and 1atm, in cm 2/s is. 0.1834
It is the actual response obtained from the control system. It may or may not be equal to the the specified response response implied implied by the input. input. Output A control system in which the control action is somehow dependent on the output. Closed-loop control system A property of a closed-loop system which permits the output (or some other controlled variable) to be compared with the input to the system (or the input to some other internally situated component or subsystem) so that the appropriate control action may be formed as some fraction of the output and input. Feedback input. Feedback control control system A frequency response measure of how well the system responds to variations in the input signal. Bandwidth
The diffusivity of the air in ethyl alcohol at 25ºC and 3 atm in ft 2/hr is 0.1744 Using the appropriate transport analogy, analogy, estimate the MTC in ft/hr for NH 3air-water system in a wetted wall column where N re=25 000, N sc=1.8 and the average velocity of the gas is 1.2 ft/s. 8.904 Acetic acid is diffusing in aqueous solution at 298K inside a 2-cm diameter tube 100cm long. Determine the total diffusion rate of acetic acid in gmole/s if the concentration at one end is 0.125 and on the other end 0.051 gmole/cm3. 2.93 x 10 -8 A 4mm diameter tube, 40cm long, closed at one end and standing vertically on its closed end, is partially filled with a liquid up to 18mm from the open top. A gentle stream of air is flowing across the top of the tube. The
A signal defined at, or of interest at, only discrete (distinct) instants of the variable (upon which it depends). a digital signal A device that converts an analog or continuous signal into a discrete or digital signal. analog-to digital (A/D) converter It is used to convert one signal or energy form into another. Transducer The part of the deviation of the response which approaches zero as time approaches infinity. Steady state response The integral of a unit step function is also known as. Unit ramp function
When the total number of variables in a process is greater than the number of independent equations that can be set-up, the process is said to be. Underspecified A control structure with two feedback controllers with the output of the primary controller controller changing the set-point set-point of the secondary secondary controller controller whose output goes to the final controller. Cascade control A type of advanced control system that identifies continuously online the parameters of the process as they change and returns the controller appropriately. Adaptive appropriately. Adaptive control control A sensor usually made of a semiconductor that utilizes the effect of temperature on the resistance to current is called a. thermistor Given the characteristics equation of a closed loop transfer function, 2s 3+4s2 +4s+12= 0. The system is. Unstable
Consider the characteristic equation of a certain closed-loop control system, S3 + 3S 2 + ( K + 2)S + 4 = 0. The range of K so that system is stable is. K>0.5328 Write the transfer function of a system with a gain factor of 2, poles at 0, -3 and at -1±2j and zeroes -2±j. 2(s2 + 4s + 5)/ s(s+3)( s 2 + 2s +5) The amplitude ratio for the transfer function 2/(s + 2) for ω=2 is. 0.707 The phase angle for the transfer function given in the Problem is__degrees. -45 A sinusoidal input X= 2sin2t is applied to a system with the transfer function G(s) = 2/s (s + 2). The steady state output as a function of t is. Y= 0.707 sin (2t – (2t – 135) 135) The gain margin of a system with a transfer function of 1/(s +1) 3 is. 8
A system has poles at -1, -5 and zeroes at 1 and -2. Is the system stable or not? Stable
The phase margin of the system in the Problem is___ degrees. -180
If a step function is applied to the input of a system and the output is of the form Y=t, is the system stable or unstable? Unstable
The range of value of K for a system with characteristics characteristics equation given by s4 + 6s3 + 11s 2 + 6s + K = 0 is. 0
If a step function is applied to the input of a system and the output remains below a certain level for all all time, is the the system necessarily necessarily stable? stable? False Is the system with a transfer function Y(s) = (s-1)/(s+2) (s 2+4) stable or unstable? Stable A proportional controller exhibits a large offset. This offset can be eliminated without altering the proportional constant K C by. adding an integral control If a step function is applied to the input of a system and the output is of the form Y=e tsint, the system is. Unstable A spring motion is i s described by the differential equation x’’(t) + 5x(t) + 6x(t) = 0. The motion of the spring is. Overdamped A PI controller of a first order process is subjected to a unit step input. If the integral constant is fixed, decreasing the proportional gain will. Increase the the overshoot In the control of pressure in a distillation column, there is no need to include. Derivative control control The integral of a Dirac function is a. Step function A PID controlled process has a highly oscillating response. response. The process can be stabilized stabilized by. Decreasing by. Decreasing proportional proportional gain. gain. A PI controller of a first order process is subjected to a unit step input. If the integral constant is fixed, increasing the proportional gain will. Decrease the overshoot A pneumatic proportional controller is used to control the temperature within the range of 60ºF to 100ºF. The controller is adjusted so that the output pressure goes from from 3 psi, with with the valve fully open, to 15 psi, with the valve fully closed, as the measured temperature goes from 71ºF to 75ºF with the set point held constant. The gain of the control element in psi/ºF is. 3 The proportional band of the above controller is. 10% A thermometer with a time constant of 0.2 min is placed in a temperature bath, and after the thermometer thermometer comes to equilibrium with the bath, the temperature of the bath is increased linearly with the time at a rate of 1 degree per min. The difference between the indicated temperature and the bath temperature after 1.0 min is. 0.20º
