General Chemistry 1. Board Problem, January 1974 A. Write the type of formula _______1. Paraffin hydrocarbon _______2. Olefin series _______3. Acetylene Series _______4. Organic alcohols _______5. Ethers
_______6. Aldehydes _______7. Ketones _______8. Organic acids _______9. Amine ______10. Amide
B. Write the structural formula and its derivatives _______1. Monochlorobenzene _______2. Phenol _______3. Aniline _______4. Toluene _______5. O-xylene
_______6. Naphthalene _______7. Anthracene _______8. Phenanthrene _______9. O-cresol _______10. Nitrobenzene
C. Atom of an element with atomic mass=207 and atomic number=82. Determine: _______1. Group number _______4. Normal valence _______2. Period number _______5. Metallic or Non-metallic _______3. Number of neutrons _______6. Acidic or basic 2. Board Problem, October 1977 A. Complete and balance the following equations 1. CaCO3 + H2SO4 = CaSO4 2. Zn + HCl = ZnCl2 3. Fe + CuSO4 = FeSO4 + 4. KClO3 = KCl + O2 5. Cu2O + O2 = CuO 6. Na2CO3 + NaOH = NaCl +
+ + Cu CO2
CO2 H2
+
+
H2O
H2O
B. Give the balance equation and material required to produce 200 g of O 2. 1. KClO3 = KCl + O2 2. KNO3 = KNO2 + O2 3. HgO = Hg + O2 3. Board Problem, April 1978 A. What is the silver content of a 2 g silver coin which produces 1.66 g AgSCN precipitate? B.
What is the pH of 0.1M monoprotic acid solution which is 1.0% ionized?
C.
How many ml of a 12 N HCl solution is needed to neutralize 100 ml of a 1.2M Ba (OH) 2 solution?
4. Board Problem, October 1979 Calculate the empirical of a compound with the following composition: 22.8%Na, 21.7%B, and 55.4% O. 5. Board Problem, October 1980 Photosynthesis is the reaction of CO 2 and H2O in sunlight to form glucose and O2. For a 264 g CO2 and 108g H2O, calculate the weight of the products. 6. Board Problems October 1977 True or False ______1. O2 is the most abundant of the elements. ______2. Equal volumes of all gases under the same temperature and pressure contain the same number of molecules. ______3. Valences of the same element could either be positive or negative. ______4. Ozone is the allotrope of O2. ______5. Metal and non-metal oxides react with water to form hydroxides. ______6. At T=K, the volume of gas varies inversely with pressure. ______7. The three states of matter are solid, liquid and gas. ______8. In the triclinic crystal system, three axes of equal length intersect each other at oblique angles. ______9. Chemical equilibrium is a state where reactions are opposite in effect and have the same velocity. _____10. Li, K, and Na are called alkali metals. _____11. The periodic law states that properties of the chemical elements are periodic functions of their atomic weights. _____12. The atoms of the radioactive elements are complex and these integrate emitting alpha and beta particles. _____13. The atomic number of O2 is 8, 2 in the first shell and 6 in the second. _____14. Transmutations cannot be caused by fast moving protons and deuterons. _____15. Equal quantities of a pH 2 acid and pH 12 base always give a pH 7 solution. _____16. Arrhenius postulated that ionization of many solutes is practically complete in dilute solutions. _____17. The smelting of an ore is the production of the metal in the molten state by means of a furnace process.
_____18. Metals are extracted from gangue in a blast furnace. _____19. Limestone is a suitable flux for ores containing silica. _____20. Metals cannot be separated from low grade ores by simple leaching process. 7. Board Problem, April 1978 Matching type _______1. Hydroxides _______2. Esters _______3. Ethers _______4. Monohydric alcohol _______5. Synthetic detergents _______6. Dialysis _______7. Organic Acids _______8. Aldehydes _______9. Isotopes ______10. Allotropes
a. RCOOR b. solutions of metallic oxides c. ROR d. methanol e. alkyl-aryl sulfonate f. substances that keep pH constant g. same atomic mass different atomic number h. molecular modifications i. chemically different but the same atomic mass j. Extraction of solids from solution by diffusion through membrane k. RCHO l. RCOOH
8. Board Problem, April 1979 True or False ________1. In an exothermic reaction, heat is produced. ________2. In an endothermic reaction, heat is absorbed. ________3. Elements combine or displace each other according to its equivalent weight. ________4. The Law of conservation is true for both mass and energy. ________5. Elements in a given group become less metallic with decrease in atomic number. ________6. The temperature of a rapidly expanding gas goes up. ________7. Physical change does not alter composition. ________8. A base gives an alkaline solution. ________9. Diamond is an example of a covalent solid. _______10. Cathode is negative. _______11. An ionic solid conducts electricity in the molten state. _______12. In the liquefaction of air, N2 liquefies first. _______13. Activation energy is the minimum energy required for reaction. _______14. Hydrocarbon contains only carbon and hydrogen. _______15. Members of a homologue differ by CH2. _______16. Isomers have the same composition and molecular weight. _______17. The formula of a tertiary alcohol is R3COH. _______18. The formula for ketone is R2O. _______19. BOD means biochemical oxygen demand. _______20. Anaerobic means without oxygen. 9. Board Problem January 1974 Matching Type ________1. Isomer ________2. Polymer ________3. Lucite ________4. Isoprene ________5. Co-polymer ________6. Cellulose ________7. Photosynthesis ________8. Fructose ________9. Cellophane _______10. Nylon
a. Products of 2 different polymerizing units. b. Synthetic rubber c. Cotton d. Synthetic silk e. Viscous process f. Sugar g. Plexi glass h. Meta; Ortho; Para i. Polyvinyl chloride j. Light to chemical energy
10. Board Problem May 1982 Write the chemical formula of the reactants, the products formed. Complete and balance the equation. Indicate the type of reaction or process involved. 1. Muriatic acid + Milk of lime 2. Brine + Electricity 3. Hydrated gypsum + Dry heat (400oC) 4. Ethyl alcohol + Acetic acid 5. Ethylene + Hydrogen (190oC) 11. Board Problem October 1979 Fill in the blanks
________1. Marsh gas. ________2. Product of alcohol and Aldehyde. ________3. Reaction between nitric acid and organic compounds. ________4. Reaction between sulfuric acid and organic compounds ________5. Industrial process of ammonia manufacturing. ________6. Wood alcohol. ________7. Common name of carbon tetrachloride. ________8. Alcohol from sugar fermentation. ________9. Group common to aldehydes and ketones _______10. Compounds that twist the polarized light to the right. _______11. Reaction between strong base and an ester. _______12. Analysis involves procedures permitting the identification of ions in solutions. _______13. Analysis involves the determination of the amounts of specific substances. _______14. Solution of weak acid containing high concentration of one of its salt. _______15. Indication of acidity or alkalinity. _______16. Mass of pure caustic soda = 36g of pure HCl _______17. Volume of 1 N sulfuric acid solution that will neutralize 10 ml 1N NaOH. _______18. Mass of Ag present in 100g AgCl. _______19. Mass of copper equivalent to 80ml of 0.1N sodium thiosulfate. _______20. Mass of BaSO4 precipitated by 10 ml 0.1N Na2SO4 from BaCl2. 12. Board Problem October 1979 Matching Type ________1. Acetylene ________2. Ethyl alcohol ________3. Cane sugar ________4. Wood alcohol ________5. Catalyst ________6. Osmosis ________7. Isomers ________8. Dry ice ________9. Reduction _______10. Acidic _______11. Basic _______12. Buffer _______13. Phenolphthalein _______14. Valance _______15. Isotopes _______16. Ionization _______17. Neutralization _______18. Polymerization _______19. Limestone _______20. Glycerine
13. Board Problem, October 1980 Matching type _______1. Fourdrinier _______2. Distillation column _______3. Expellers _______4. Digester _______5. Spray drier _______6. Saponification kettle _______7. Oak barrels _______8. Pigments _______9. Crusher ______10. Electrolytic cells
14. Board Problems, November 1982 Write the chemical formula of the compound ________1. Formaldehyde
a. Substances altering reaction rate b. Substance with same formula but different chemical properties c. Elements of the same properties but different atomic weights d. Electron gain e. pH > 7 f. pH < 7 g. C3H5 (OH) 3 h. CO2 i. C2H5OH j. C2H2 k. CaCO3 l. C12H22O11 m. CH3OH n. Diffusion through membrane o. Indicator p. Combining power of an element q. Acid + Alkali r. Process of building up to larger molecules from small one s. Formation of charged particles. t. Common ion effect
a. wine b. soap c. paper making d. paint e. coconut oil f. baking g. mining / metallurgy h. alcohol i. Powder detergent j. caustic/ chloride k. glass making l. flour milling m. pulp making n. fertilizer
________6. Chloroform
________2. Urea ________3. Ethanol ________4. Glucose ________5. Methane
________7. Acetyl-Salicylic acid ________8. Stearic acid ________9. O-phthalic acid _______10. Trinitrotoluene
15. Board Problem, May 1983 A. Write the chemical formula of the compound 1. Soda ash __________ 2. Caustic soda __________ 3. Ethanol __________ 4. Gypsum __________ 5. Muriatic acid __________ B. Complete and balance the following reactions: 1. Cu + HNO3 (dilute) 2. KMnO4 + HBr
16. Board Problem, November 1983 Find the empirical formula of a compound whose percentage composition by weight is as follows: 45.9% K, 16.5% N, and 37.6% O Mass Relationships 17. Board Problem, January 1974 From the following data compute the amount of raw materials required to produce 100 tons of caustic soda by caustication process Data: a. limestone 96% calcium carbonate b. lime conversion efficiency 90% c. soda ash 98% 18. Board Problem, April 1978 Calculate the theoretical quantities of all raw materials needed to produce 100 MT of soda ash daily by the Solvay process. 19. Board Problem, October 1978 What volume of oxygen gas collected over water at 20 oC and 750mmHg can be obtained by the decomposition of 170g potassium chlorate? 20. Board Problem, October 1978 What volume of air measured at 25oC and 740mmHg is required to burn 3L of gasoline? Gasoline is a mixture with average composition C 7H14 (ρ= 0.7 g/ml). 21. Board Problem, October 1978 In the lime soda process for caustic soda manufacture, lime is made to react with water and then with soda ash. The composition of raw materials: Lime: 54% calcium oxide, 1.5% magnesium oxide and inerts Soda ash: 50% sodium oxide and inerts a. How many metric tons of lime and soda ash will be needed to produce 100 MT of 25% liquid sodium hydroxide? b. How many metric tons of calcium carbonate by-product will be produced? 22. Board Problem, October 1978 3000 MT of a 6-10-16 fertilizer was prepared by mixing ammonium sulfate (95% purity), phosphoric acid (95% purity), muriate of potash (95% purity), and gypsum (90% purity). Calculate how much of each was used. 23. Board Problem, May 1990 A 0.5g sample of limestone with inert materials was treated with HCl and 211ml of CO 2 was liberated. The gas was measured dry at 25 oC and 763 mmHg. Calculate the % calcium oxide in the sample. 24. Board Problem, November 1982 If 10kg of sodium were made to react with water, calculate the following : a. Weight of water involved in the reaction b. Moles of sodium hydroxide produced c. Standard ft3 of hydrogen liberated during the reaction d. Amount of water to be added to produce 0.1N solution. 25. Board Problem, November 1983 If 40g of phosphoric acid react with 60g magnesium carbonate, calculate: a. Mass of magnesium sulfate produced b. Mass of carbon dioxide produced
c. Volume of gas at STP 26. Board Problem, November 1983 Copper smelter is using copper sulfide concentrate containing 30% copper and 40% sulfur. The plant employs Autokumpu process with pure oxygen to produce at its rate capacity of 130,000 MT per year of 99.9% copper. The following equation may be assumed during the smelting: Copper sulfide + oxygen = copper+ sulfur dioxide Compute a. Feed rate per hour of the concentrate for 330 days/year operation. b. Oxygen requirements in tons per hour. 27. Board Problem, May 1985 Ethyl alcohol and carbon dioxide are obtained from hydrolysis of sucrose. At T= 80 oF and 1atm, how many kilos of alcohol and liters of gas can be obtained from a 1 metric ton of sucrose? 28. Board Problem, October 1978 It is desired to produce phenol by reacting chlorobenzene and sodium hydroxide. 1000kg of phenol are produced from reacting 1,320kg of chlorobenzene and 1,200kg of sodium hydroxide, what is the: a. % excess b. % yield Solutions/ Colligative Properties 29. Board Problem, April 1979/ May 1983 For a 25g sucrose dissolved in 1kg of water at 70oC, calculate: a. Vapor pressure of the solution c. Freezing point b. Boiling point d. Osmotic pressure 30. Board Problem, May 1980 For a 1% sugar solution with a density of 1.03 g/ml, calculate: a. Vapor pressure of the solution c. Freezing point b. Boiling point d. Osmotic pressure 31. Board Problem, October 1980 A solution containing 4.5g of an unknown compound in 100g of benzene gave a freezing point of 4.02 oC (kf= 5.12oC, Tfo= 5.5oC). Give the molecular weight of the unknown substance. 32. Board Problem, May 1982 At 60oC, the vapor pressure of Ethyl alcohol is 352.7 mmHg and that of methyl alcohol is 625 mmHg. If the two alcohols are mixed 50/50 by weight at that temperature, assuming ideal solution, what will be the composition of the vapor above the solution? 33. Board Problem, November 1982 Find the molecular weight of the liquid from the following data obtained from measuring the vapor pressure of the liquid by the gas saturation method. Volume of oxygen at 740mmHg and 30oC = 5.6 ml Barometric pressure = 740 mmHg Temperature = 30oC Loss in weight of the solid = 1.195g Vapor pressure of the liquid at 30oC = 78.2 mmHg 34. Board Problem, November 1982 By dissolving 22.5g sodium carbonate decahydrate in water and adding water until the total volume is 200 cc, a solution is made having a density of 1.04 g/ml. Calculate: a. Molarity b. Normality c. Mole fraction of the solute 35. Board Problem, May 1985 0.5g of N with MW of 160g/mol is dissolved in 10g of solvent S. The boiling point of the solution is 124.8 oC. If 0.4g of M is dissolved in 12g of the same solvent S, the boiling point of the solution is 125.2oC. Boiling point of the solvent is 122oC. Calculate the MW of M. Chemical Equilibrium 36. Board Problem, October 1980 One tenth of a mole of phosphorus pentachloride is heated to 250 oC in a 2li vessel. At this temperature, the dissociation proceeds according to the reaction with Kc= 0.0414. Calculate the concentration of Cl 2 in moles/li. PCl5 (g) = PCl3 (g) + Cl2 (g) 37. Board Problem, May 1981 Calculate the total pressure which must be applied to a mixture of 3 parts hydrogen and 1 part nitrogen to give a mixture containing 10% ammonia at 400oC, Kp= 1.64 x 10-4.
38. Board Problem, November 1982 Calculate the mole percentage of ammonia present at equilibrium at 450 oC when the total pressure is 100 atm, and the molar ratio of hydrogen to nitrogen is 3 to 1. Refer to PhyChem by Maron and Lando (Table 10-1, p. 364), for the average value of K.
39. Board Problem, May 1983 PCl5 (g) dissociates into PCl3 (g) and Cl2 (g) when heated at 250oC at 1atm. If the density of the gas mixture at equilibrium is 4.4g/li at 250 oC and 1 atm, calculate: a. Mole fraction of the reactant b. Composition of the gas mixture at equilibrium 40. Board Problem, November 1985 The total pressure for the system is 32 mmHg at 750 oC. The partial pressure of water at that temperature is 23.7 mmHg. Find the value of Kp at the same temperature for the reaction. ½SnO2 (s) + H2 (g) = ½Sn (s) + H2O (g) The reaction below has a value of Kp= 0.771 at the same temperature: H2 (g) + CO2 (g) = CO (g) + H2O (g) 41. Board Problem, May 1981 a. Calculate the (H+) in a 0.1M HCNO solution. b. Degree of ionization, Ka= 2 x 10-4 c. pH of the solution 42. Board Problem, November 1982 At 3000oC and 1atm, carbon dioxide is 40% dissociated. If 50 li of carbon dioxide at 20 oC and 1 atm are heated to 3000oC at constant pressure, what volume of gas will result assuming it behaves ideally. The reaction is CO 2 (g) = CO (g) + ½O2 (g) Analytical Chemistry 43. Board Problem, January 1974 In the process of neutralization of Na2CO3 with HCl, the amount of 0.1N HCl used is 35ml per 100ml of Na2CO3 solution. Calculate: a. Amount of HCl needed to reach end point b. Concentration in g/ml of the Na2CO3 solution 44. Board Problem, October 1979 Three gmole HCl and 80g of NaOH were placed in a liter of water a. Show the balanced equation involved b. Is the resulting solution acidic or basic? c. How much of the dominant substance is in excess? 45. Board Problem, May 1980 A 0.5g sample of iron oxide (Fe 2O3 with inert materials) was dissolved in H 2SO4 and completely reduced and titrated with 13.3 ml of KMnO 4 (1 ml of KMnO4 is equivalent to 0.0126g H2C2O4∙2H2O). What is the % Fe2O3 in the sample? 46. Board Problem, May 1981 A soda ash plant utilizing Solvay process calcines sodium bicarbonate to soda ash according to the reaction: NaHCO3 = Na2CO3 + H2O + CO2 a. For the purpose of a rapid laboratory calculation, evolve a simple formula to show efficiency of calcination in terms of the following laboratory data: V1 = volume of titrating agent used on sample from start to phenolphthalein end point V2 = volume of titrating agent used on sample from the phenolphthalein end point to the methyl orange end point. Assuming the titrating agent is 0.1N acid. b. % Purity of the product for a 94.7% calcination efficiency. 47. Board Problem, May 1981 a. Calculate the molarity, molality, and normality of 10g of NaOH in 500ml of H 2O. b. Calculate the number of grams of H2SO4 in 100ml of water that will completely neutralize the solution in A. 48. Board Problem, May 1982 A 20% aqueous solution of sodium carbonate and a 25% aqueous solution of calcium hydroxide were reacted to produce caustic soda solution. The precipitate formed was analyzed to contain 5% water, 1% NaOH and 94% CaCO 3. Calculate: a. Concentration of the NaOH solution produced b. % recovery of NaOH 49. Board Problem, May 1983
In the analysis of a feldspar sample weighing 0.42g mixture of KCl and NaCl is obtained which was found to weigh 0.072g. The same feldspar was found to contain 0.16g K2PtCl6. Calculate the Na2O in the feldspar. 50. Board Problem, May 1983 A sample weighing 0.6234g that might contain a mixture of NaOH + Na 2CO3 or Na2CO3 + NaHCO3 is titrated with 0.1062M HCl by the two indicator method. With phenolphthalein end point, 40.38ml of acid was used. The titration is continued after adding methyl orange, and an additional 12.38ml of acid was used. a. Identify the mixture of bases in the sample b. Calculate the % of each base in the sample 51. Board Problem, May 1984 A sample of impure magnetite (Fe 3O4) weighing 0.5g was converted by chemical reaction to Fe 2O3. The iron oxide, Fe 2O3, was found to weigh 0.41g. Determine the % Fe3O4 n the magnetite. 52. Board Problem, May 1984 A sample containing only ferric oxide (Fe 2O3) and aluminum oxide (Al2O3) weighs 10g. This sample is heated with sufficient amount of hydrogen gas to reduce all the iron oxide to elemental iron. The aluminum oxide remained unaffected in the process and the dry sample was found to weigh 8.58g. Calculate the % Al in the original sample.
53. Board Problem, November 1984 25.3ml of 0.1065N HCl are added to 92.2ml of 0.603N H2SO4. To the mixture, 60ml of 1N KOH are added. a. Is the final mixture acidic or basic? b. What volume of 0.1N acid or alkali must be added to neutralize the solution? Electrochemistry 54. Board Problem, October 1977 At 25oC, the free energy of formation of H2O (l) is -56,700 cal/mol, while that of its ionization to H+ and OH- ions is 19,050 cal/mol. a. What will be the reversible EMF at 25oC of the cell? H2 (g, 1 atm); H+ || OH-; O2 (g, 1 atm) b. What will be the single electronic potentials of the oxygen electrode? 55. Board Problem, April 1978 A uniform current deposits 0.6332g of Ag in 90 minutes. a. What volume of hydrogen gas at 25oC and 740 mmHg measured over water (Pv = 23.7mmHg) would it liberate in 60 min? b. How long would it take this current to deposit a gram of copper? 56. Board Problem, May 1983 a. Write the cell which will have the following cell reaction. Hg + Sn++ = Hg++ o ∆ o b. Calculate the E of the cell and the F of the reaction. c. Will Hg (s) displace Sn++ from its salt?
+
Sn
57. Board Problem, November 1983 74.55g KCl is electrolyzed between AgCl electrodes at 25 oC. 2.48g of Ag were deposited on each of 2 coulometer in series at the transference cell over a period of 20.5hr at a current of 0.03Amp. After electrolysis, the anode compartment contained 121.4g of solution with 6.51% by weight of KCl while the cathode compartment had 125.7g of solution with 7.15% KCl, which did not change significantly during the electrolysis. Calculate the transference number of the cation and anion. 58. Board Problem, May 1984 A saturated solution of AgCl placed in a conductance cell whose constant is 0.1802/cm had R= 67,950 ohms. At 25 oC, R water = 212,180 ohms in the same cell. Calculate Ksp of AgCl in water. IoAg+ = 61.9 and IoCl+ = 76.3. Gas Law 59. Board Problem, October 1977 10.5li of nitrogen at 25oC and 760mmHg are bubbled through an aqueous solution of a non-volatile solute, whereby the solution loses 0.2455g in weight. If the total pressure of the solution above is 760mmHg, what is the vapor pressure of the solution and the mole fraction of solute in solution? 60. Board Problem, April 1979 The time of outflow of a diatomic gas through a small opening is 24.4 minutes and the corresponding time for hydrogen is 5.5min. a. What is the MW of the diatomic gas? b. At 100oC, what is the root mean square velocity? c. How many grams of this gas will be needed to fill a sphere 5 ft ID at -10 oC and 5 atm?
61. Board Problem, May 1980 A mixture of hydrocarbon vapor contains 80kg of benzene, 80kg of toluene and 60kg Xylene. Calculate: a. Volume in m3 of vapor mixture at 300oF and 444 mmHg. b. Density of mixture in g/ml 62. Board Problem, May 1981 Calculate the work done when a mole of sulfur dioxide at 27 oC expands reversible and isothermally from 1 to 10 li, assuming the gas follows Van der Waals equation. Van der Waals constant a= 6.714, b= 0.05636 63. Board Problem, November 1982 A mixture of 0.2g nitrogen and 0.1g hydrogen is to be stored at 760 mmHg and 25 oC. What must be the volume of the container if it is assumed that here is no interaction between the two gases? 64. Board Problem, May 1983 The following data were gathered in the determination of a hydrogen gas; 92.3% by wt at -9 oC at various pressures. Determine the exact MW of the hydrocarbon and identify the gas. Pressure (atm) 1 2 3 Density (g/li) 1.45 3.4 5.85 65. Board Problem, November 1984 When evacuated or empty, a gas density bulb weighs 29.3215g. First, carbon dioxide was used to fill the gas density bulb at 40 oC and 1 atm and weighed 30.0079g. Then the bulb was evacuated and filled with a mixture of CO and CO 2 under the same temperature and pressure. With this mixture the bulb weighs 29.9332g. What was the % CO in the gas mixture? 66. Board Problem, November 1984 The organic compound showed the following analysis using the Victor Meyer apparatus By wt Carbon 37.5% Hydrogen 12.5% Oxygen 50.0% The organic compound of 0.25g vaporized displacing 100ml of air measured over water at 25 oC and 748 mmHg. What is the MW of the compound? 67. Board Problem, October 1979 A 500ml sample of a gas collected at 80oC and 730 mmHg pressure weighed 1.5g. What is the MW of the gas? 68. Board Problem, October 1980 1.2g of a gaseous hydrocarbon containing 80% C and 20% H by weight occupies 950ml at 20 oC and 770 mmHg. a. Determine the simplest formula of the hydrocarbon. b. Fine the MW of the HC c. Write the Molecular formula of the HC. d. Identify its family. Work/ Heat/ Thermodynamics 69. Board Problem, April 1979 A 500 lb piece of iron falls from a height of 1000ft. If the atomic weight of iron is 55.5 and neglecting air resistance, calculate the heat it liberate after hitting the hard ground in: a. ergs c. calories b. joules d. liter-atm What is the maximum rise in temperature of the piece of iron as it hits the hard ground? 70. Board Problem, April 1979 One mole of a perfect diameter gas (Cv= 5) initially at 40 oC and 10atm expands quickly (adiabatically) against a constant external pressure of 2atm until its own pressure has fallen to 2 atm. Calculate ∆S for the operation. 71. Board Problem, October 1979 A lead bullet is fired at a stationary target. What would be the muzzle velocity (in fps) so that it hits the target, its temperature would reach the melting point of lead (328oC). Assume that the temperature of the bullet before it hits the target is 28 oC and that the specific heat of lead is 0.055 BTU/lb-oF; 778 ft-lb/BTU. 72. Board Problem, May 1980 The free energies of formation at the standard state at 25 oC of liquid acetic acid, CO 2, and CH4 are -94,500, - 94,100, and -12,100cal/mol, respectively. Calculate the free energy change accompanying the decomposition of a mole of acetic acid into CO 2 and CH4. 73. Board Problem, May 1980
A fuel furnishes 7,000cal of heat per gram. Calculate the maximum work which can be obtained from in this engine which operates with the water between its boiling point and 40oC. 74. Board Problem, October 1980 Calculate the difference between the heat of combustion of methane at constant pressure and at constant volume at 27 oC when liquid water forms. 75. Board Problem, May 1980 a. Calculate the energy generated by an electric current of 10A across a voltage of 10V for 10hr, in calories. b. If this energy is used to heat water, how many grams of water can be heated from 20 oC and 100oC. 76, Board Problem, May 1982 Calculate the change in entropy in entropy units when 100g of ice at 0 oC is converted to steam at 100oC and 1atm. 77. Board Problem, November 1982 The integral heat of solution of MgCl 2 (s) at 18oC is 35,900 cal and that of MgCl 2∙6H2O is -2,950 cal. The heat of vaporization of water is 587 cal/g. Find ∆H at 18oC for the reaction. 78. Board Problem, May 1984 The vapor pressure of acetic acid at 90 oC is 293mmHg and 417mmHg at 100 oC. Assuming the latent heat of vaporization of acetic acid is given within the given temperature range, calculate: a. Molar latent heat of vaporization b. Normal boiling point of acetic acid 79. Board Problem, May 1984 Calculate the degree of dissociation of SO3 at 600oK and 0.5 atm. At 600oK: ∆G= 19,759cal and ∆H= 46,980cal. SO3 (g) + O2 (g)
=
SO2
(g)
80. Board Problem, November 1985 A newly designed refrigerator has a capacity of 3,140 watts and input rating of 735 watts. What is the coefficient of performance of the refrigerator and the heat transfer rate in the condenser? Chemical Engineering Calculations I 81. Board Problem, April 1978 A mixture of ammonia and air at a pressure of 745mmHg and a temperature of 40 oC contains 4.9% ammonia by volume. The gas is passed at a rate of 100 ft3 per min through an absorption tower in which only ammonia is removed. The gas leaves the tower at a pressure of 740mmHg at 20 oC and contains 0.13% ammonia by volume. Using the ideal gas law, calculate: a. Rate of flow of gases leaving the tower (ft 3/min). b. Weight of ammonia absorbed in the tower per min. 82. Board Problem, May 1981 One cu. cm. of a certain activated charcoal has a surface area of 1,000 m 2. Assuming complete surface coverage, how much ammonia at standard conditions, could be absorbed on the surface of 45cc of activated carbon? Assume that the ammonia molecules just touch each other on a plane. 83. Board Problem, November 1983 A solvent water mixture is to be distilled at 95 oC. The vapor pressure of the solvent at this temperature is 130 mmHg and that of the water is 640 mmHg. The solvent is immiscible in water and has a MW= 150. Calculate the weight of the solvent in kilos that will be carried over into the distillate with 200kg water. 84. Board Problem, November 1984 At a fertilizer plant drier, the special formula 14-14-10 requires the removal of 200 lb of water per hour to assure good granulation. Air at 70 oF and 50% RH enters the drier and leaves at 140oF and 80% RH. What is the weight of the bone-dry air used per hr? Assume the barometer reading at 760 mmHg. 85. Board Problem, November 1985 It is desired to produce copper cyanide by first converting it to copper sulfate. The copper scraps (bronze, bullet shells) are to be charged, together with sulfuric acid to a reactor. Assuming the products are copper sulfate, water, and sulfur dioxide; neglecting impurities; calculate: how much is required for a. Copper b. Sulfuric acid (90% by wt) if the vessel is closed and 40lb of sulfuric dioxide was collected. 86. Board Problem, April 1979 A cement company uses 3,000MT of gypsum a month. If 40MT of this gypsum are needed for every 1,000MT of clinker to produce Portland cement: a. How many MT of clinker is produced monthly?
b. How many MT of limestone (53% CaO) per month does this represent? c. Give the analysis of the cement if the clinker analysis is as follows: CaO= 61.92%, Fe2O3= 6.24%, SiO2= 20.64%, Al2O3= 7.2% 87. Board Problem, April 1979 A fertilizer plant produces 120,000 MT of 10-6-10 fertilizer annually from ammonium sulfate (20%N), diammonium phosphate (18%N, 46% P2O5), potassium chloride (60% K2O) and gypsum as filler. How much of the materials above are used by the plant annually? Note: A 10- 6- 10 contains: 10%N, 6%P as P2O5, and 10% potash as K2O. 88. Board Problem, May 1982 Oil and light solids are removed from 20,000 gal/hr of factory wastewater in a froth floatation plant. Treatment requires 0.04 ft 3 (STP) of air per gallon of wastewater. Air is fed into the water at a depth of 10ft from the surface, at a pressure equal to the hydrostatic pressure of the water at the point of entry. The air bubbles enter the water at an average diameter of 1mm. If water temperature is constant at 700 oFand barometric pressure is 29.7 inHg, calculate: a. Air feed rate at STP b. Average diameter of the air bubbles as they reach the water surface. 89. Board Problem, November 1983 The dilute sulfur dioxide by-product of the Leyte copper smelter is converted first into sulfuric acid to avoid pollution and get some added values from the sulfur. The Philippine phosphate plant nearby will use the sulfuric acid to make ammonium sulfate and ammonium phosphate fertilizers. Calculate the sulfuric acid production per day when the smelter is operating at 60% of its rated capacity (130,000 tons of copper per year and the Philex concentrate has 40% total sulfur from copper and iron sulfides.). 90. Board Problem, May 1985 A cold process soap is made by mixing 340ml of 35 o Baume (25o) NaOH solution with 660ml coconut oil poured into molds and allowed to stand and harden. Calculate: a. % NaOH in 35o Baume NaOH solution. b. % excess or shortage of NaOH used, if coconut oil has a saponification number of 260. MW= 205, Sp.gr.= 0.9. Chemical Engineering Calculations II 91. Board Problem, January 1974 A natural gas is known to be composed only of methane, ethane and nitrogen. The volume% of nitrogen is 20% when burned. The Orsat analysis of the flue gas shows 7.8% CO2, 7.4% O2, and 84.8%N2. Determine: a. Volume of methane and ethane. b. % excess air. 92. Board Problem, April 1974 A furnace fires a fuel oil containing 82% carbon, 17% hydrogen and 1% Sulfur using 10% excess air. Assuming that the combustion of C to CO2 is only 90% complete and that all the sulfur is burned to SO2, calculate the complete analysis of the wet flue gas. 93. Board Problem, October 1978 A rotary drier burns a fuel with dry air at 40 oF and 30.1 inHg. The oil contains only carbon and hydrogen. Analysis of the flue gas shows 12.9% CO2, 3.8% O2 and 83.3%N2. Calculate: a. % excess air d. ft3 flue gas (40oF and 30.1 inHg) per lb oil b. Weight % of carbon in oil e. Partial pressure of water vapor in the stack gas c. ft3 air/lb oil 94. Board Problem, October 1979 A furnace coal uses coal which analyzes 70.4%C, 4.8%H 2, 9.4%ash, 11.8%O2, and negligible N and S. If the furnace is fired with 50% excess air, calculate the flue gas analysis assuming complete combustion. 95. Board Problem, May 1980 Calculate the % heating value lost in the refuse for this certain type of coal (negligible N and S) with a heating value of 14,000 BTU/lb. Proximate Analysis Proximate Analysis of Refuse 4.7% moisture 28% FC 24.3% VCM 7% VCM 9.6% Ash 65% Ash 61.4% FC 96. Board Problem, May 1981 A low grade coal with heating value of 11,000 BTU/lb is used to fire a boiler at the rate of 600 lb/hr. With the following analysis presented. a. Calculate % heating value lost in the refuse b. Having a heat transfer efficiency of 60%, calculate the 1,150 BTU/lb steam produced/ hr. Proximate Analysis Proximate Analysis of refuse 10% Ash 19% FC 30% VCM 10% VCM
57% FC
50% ash
97. Board Problem, May 1982 The ultimate analysis of a Bituminous coal, as received, is 77.5%C, 3.7%H 2, 1.5%N2, 4.3%O2, 0.5%S, 6.5% ash and 6.0%water. a. Convert this analysis to dry basis. b. Convert this analysis to dry and ashless basis. c. If this coal as received is burned at a rate of 100MT/hr and the refuse is analyzed as being 10% combustible (carbon in the ash), how many kilos of refuse/hr must be handled? 98. Board Problem, May 1982 Formaldehyde is made by the catalytic air oxidation of methanol. When the process is operating properly, there is a 30% conversion of methanol to formaldehyde. Suddenly, the supervising Chemical Engineer noted a drop in formaldehyde production. An analysis of a sample taken at this time showed 63.1%N2, 13.4%O2, 5.9%H2O, 4.1%CHO, 12.3%methanol and 1.2% HCOOH. Calculate: a. % conversion of methanol to formaldehyde b. Moles air/ mol methanol 99. Board Problem, November 1982 A burner burns a fuel gas entering at 70 oF and 1atm, employing 20% excess air with the same condition as the fuel gas. Assuming complete combustion, give the orsat analysis of the flue gas. Fuel gas composition (%vol) is as follows: 1%O 2, 3%CO2, 33%CO, 40%H2, 1%Benzene, 6%ethylene, 6%N2, 10%Paraffins (C12H44). 100. Board Problem, November 1982 1 x 106 MT of an ore, containing 3.0% copper sulfide, is concentrated by floatation, with a 90% recovery of the sulfide. Calculate: a. Tons of cuprous sulfide recovered. b. Tons of sulfur dioxide liberated by roasting the sulfide c. Tons of pure copper metal obtained by electrolytic refining of Blister copper, if recovery is 100%. 101. Board Problem, May 1983 Semirara coal (negligible N and S) has the following analysis: 75.6%C, 9.6%O 2, 8.8%ash, 6.0%H2, and 20% excess air used. Due to faulty combustion, 85% is completely burned, the rest to CO. Calculate the dry air supplied (m 3) per kg coal at 40oC and 1atm. 102. Board Problem, May 1983 Absolute alcohol (ethyl alcohol) is burned using 20% excess air. Give the complete analysis of the combustion products assuming complete combustion. 103. Board Problem, May 1995 The actual process by which a close system changes from an initial state, I, to a final state, f, as shown in the PV diagram below: 300 200 P (Pa) 100 0
1
2
3
4
V (m3)
The total heat added to the system is 500J, the change in enthalpy of the system is a. -100J b. 300J c. 500J
d. 1100J
Answer: 3. a. 54%, b. 3, c. 20ml 4. Na2B4O7 16. KNO2 17. Limestone= 144.68 tons, soda ash= 135.2 tons 18. NaCl= 110.38 tons/day, CaCO3= 94.3 tons/day 19. 51.93 li 20. V= 27,623 li 21. Limestone= 31.25 MT, soda ash= 38.75 MT, lime= 32.41 MT 22. Ammonium sulfate= 893.3MT, Phosphoric acid= 435.9MT, Muriate of potash= 800.9MT, gypsum=869.9MT. 23. 97.0% 24. a. 7.826kg, b. 434.78 mole, c. 171.9 ft3, d. 4,347.8 li 25. a. 53.45kg, b. 26.93kg, c. 13.71 li 26. a. 54.66, b. 4.13 27. Alcohol= 538 kg, gas= 2.88 x 105 li 28. a. 155.75%, b. 90.69% 29. a. 23.77 mmHg, b. 100.038oC, c. -0.136oC, d. 1.79 atm 30. a. 23.75 mmHg, b. 100.015oC, c. -0.055oC, d. 0.736 atm 31. 155.68 g/mol 32. 28% ethyl alcohol 33. 46,116 g/mol 34. a. 0.393M, b. 0.786N, c. 7.04 x 10-3 35. 93.33 g/mol 36. 0.0293M 37. 29.69 atm 38. 15.6% 39. a. 0.103, b. 81.32%, 9.34%, 9.34% 40. 3.7 41. a. 0.00478M, b. 4.78%, c. 2.32 42. 670 li 43. a. 17.5 ml, b. 0.001855 44. b. acidic, c. 36.5g HCl 45. 42.49% 46. a. 2V1/ (V1+V2), b. 91.85% 47. a. M=N=0.5, b. 12.25g 48. a. 10.97% wt, b. 98.98% 49. 2.90% 50. a. NaOH and Na2CO3, b. 18.77%NaOH and 23.16% Na2CO3 51. 79.26% 52. 27.90% 53. a. basic, b. 17.1 ml 54. a. Eo cell= 0.403V, b. Eo O2= 0.403V 55. a. 0.0508li, b. 8.04hr 56. b.∆Fo= 85,291 cal, c. no 57. tK+= 0.487; tCl-= 0.513 58. 1.7 x 10-10 59. 23.33 mmHg, 0.018 60. a. 39.36g/mol, b. 48,617 cm/s, c. 16,899g 61. a. 146m3, b. 1.51 x 103g/ml 62. 1,257.44 cal 63. 1.397 li 64. 25.99 g/mol; ethyne 65. 29.94%
66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 100. 101. 102.
64.14 g/mol 90.46 g/mol a. CH3, b. 29.97, c. C2H6, d. ethene; paraffin a. 6.78 x 1012, b. 677,614, c. 161,954, d. 6,688, and e. 11.37oF 478.13oK 1,216 fps -11,800 cal 1,126cal/g -1,192 cal a. 360,400cal, b. 11,472g 205.28 eu 24,546 cal a. 9,494.72cal/mol, b. 118.34oC 6.33 x 10-3 COP= 4.27; Q= 3.33 x 106 cal/hr a. 89.75, b. 0.1938 lb/min 14.1/g ammonia 338.54kg 1,782.53 Handbook/ 1,853.6 Steam table a. 39.69 lb, b. 136.11 a. 75,000, b. 87,623, c. 63.76%CaO, 20.81%SiO2, 6.29%Fe2O3, 7.26%Al2O3, SO3 Ammonium sulfate= 45,913, diammonium phosphate= 15,652, KCl= 20,000 a. 800 ft3/hr; 22.67 m3/hr, b. 1.09mm 964.20 a. 29%, b. 18% x’s a. 57.24%, b. 50.2% O2 sg= 1.45 mol, H2O= 8.5 mol a. 20.72%, b. 87.68%, c. 216.57, d. 227.3, e. 2.95 inHg CO2= 5.87 lbmol; H2O= 2.4 lbmol 5.92% a. 6.67%, b. 3,214 lb c. 7.22 MT a. 23.3%, b. 4.54% a. 27,000, b. 10,864.41, c. 21,559.32 11.01 CO2= 2 mol; O2 sg= 0.6 mol
