Essential University Physics, 3e (Wolfson) 3e (Wolfson) Chapter 17 The Thermal Behavior of Matter
1 7. 1 Co nc e pt ua lQue s t i o ns 1) If the temperature of an iron sphere is increased A) its density will increase. B) its volume will decrease. C) its density will decrease. D) its mass will decrease. E) its density will remain unchanged. Answer: C ar: 1
!) A machinist needs to remove a tight fitting pin of o f material A from a hole in a "loc# made of material B. $he machinist heats "oth the pin and the "loc# to the same high temperature and removes the pin easily. easily. %hat statement relates the coefficient of thermal e&pansion of material A to that of material B' A) (aterial B has a greater coefficient of e&pansion than does material A. B) $he situation is not possi"le "ecause heating "loc# B will shrin# the hole in the material as the material e&pands with increasing temperature. C) (aterial B has the same coefficient of e&pansion as does material A. D) (aterial A has a greater coefficient of e&pansion than does material B. Answer: A ar: 1
) $wo $wo steel spheres are made of the same material and have the same diameter* "ut one is solid and the other is hollow. If their temperature is increased "y the same amount A) the solid sphere "ecomes "igger than the hollow one. B) the hollow sphere "ecomes "igger than the solid one. C) the two spheres remain of e+ual si,e. D) the solid sphere "ecomes heavier and the hollow one "ecomes lighter. E) the solid sphere "ecomes lighter and the hollow one "ecomes heavier. Answer: C ar: 1
-) %hen a solid melts A) the temperature of the su"stance increases. B) the temperature of the su"stance decreases. C) heat energy leaves the su"stance. D) heat energy enters the su"stance. Answer: D ar: 1
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2) %hen a vapor condenses A) the temperature of the su"stance increases. B) the temperature of the su"stance decreases. C) heat energy leaves the su"stance. D) heat energy enters the su"stance. Answer: C ar: 1
0) A chun# of ice 3T 4 4 5!/6C) is added to a thermally insulated container of cold water 3T 4 4 /6C). %hat happens in the container' A) $he ice melts until thermal e+uili"rium is esta"lished. B) $he water cools down until thermal e+uili"rium is esta"lished. C) 7ome of the water free,es and the chun# of ice gets larger. D) 8one of the a"ove things happen. Answer: C ar: 1
9) A fi&ed amount of ideal gas is held in a rigid container that e&pands negligi"ly when heated. At !/6C the gas pressure is p. If we add enough heat to increase the temperature from !/6C to -/6C* the pressure will "e A) impossi"le to determine since we do not #now the num"er of moles of gas in the container. B) greater than ! p. C) less than ! p. D) e+ual to ! p. E) impossi"le to determine since we do not #now # now the volume of gas in the container. Answer: C ar: 1
) ;or a fi&ed amount of gas* if the a"solute temperature of the gas is dou"led* what happens to the pressure of the gas' A) $he answer cannot "e determined without v olume information. B) $he pressure of the gas "ecomes dou"le the original pressure. C) $he pressure of the gas "ecomes eight times the original pressure. D) $he pressure of the gas "ecomes one half the original pressure. E) $he pressure of the gas "ecomes four times the original pressure. Answer: A ar: 1
<) $he num"er of molecules in one mole of a su"stance A) depends on the molecular weight of the su"stance. B) depends on the atomic weight of the su"stance. C) depends on the density of the su"stance. D) depends on the temperature of the su"stance. E) is the same for all su"stances. Answer: E ar: 1
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1/) %hich contains more moles of material: / grams of helium gas 3=e* having atomic weight -./ g>mol) or -// grams of argon gas 3Ar* having atomic weight -/ g>mol)' A) helium B) argon C) Both contain the same num"er of moles. Answer: A ar: 1
11) If the temperature of a fi&ed amount of an ideal gas is increased* it 8ECE77A?I@ follows that A) the pressure of the gas will increase. B) the volume of the gas will increase. C) the speed of the gas molecules will increase. D) All of the a"ove statements are correct. Answer: C ar: 1
1!) A mole of o&ygen 3!) molecules and a mole of car"on dio&ide 3C!) molecules at the same temperature and pressure have A) the same average molecular speeds. B) the same num"er of atoms. C) different average #inetic energy per molecule. D) the same num"er of molecules. E) different volumes. Answer: D ar: 1
1) $he average molecular #inetic energy of a gas can "e determined "y #nowing A) only the num"er of molecules in the gas. B) only the volume of the gas. C) only the pressure of the gas. D) only the temperature of the gas. E) All of the a"ove +uantities must "e #nown to determine the average molecular #inetic energy. Answer: D ar: 1
1-) A sample of an ideal gas is slowly compressed to one5half its original volume with no change in temperature. %hat happens to the average speed of the molecules in the sample' A) It does not change. B) It "ecomes - times as great. C) It "ecomes ! times as great. D) It "ecomes 1>! as great. E) It "ecomes 1>- as great. Answer: A ar: 1
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12) A sample of an ideal gas is slowly compressed to one5half its original volume with no change in pressure. If the original root5mean5s+uare speed 3thermal speed) of the gas molecules was V * the new speed is A) V . B) !V . V . C) D) V >!. E) V > Answer: E ar: 1
10) If we dou"le the root5mean5s+uare speed 3thermal speed) of the molecules of a gas* then A) its temperature must increase "y a factor of -. B) its temperature must increase "y a factor of !. C) its temperature must increase "y a factor of . D) its pressure must increase "y a factor of !. E) its pressure must increase "y a factor of -. Answer: A ar: 1
19) A container is filled with a mi&ture of helium 3light molecules) and o& ygen 3heavy molecules) gases. A thermometer in the container reads !!6C. %hich gas molecules have the greater average #inetic energy' A) It is the same for "oth of the gases "ecause the temperatures are the same. B) $he o&ygen molecules do "ecause they are diatomic. C) $he o&ygen molecules do "ecause they are more massive. D) $he helium molecules do "ecause they are less massive. E) $he helium molecules do "ecause they are monatomic. Answer: A ar: 1
1) A container is filled with a mi&ture of helium 3light molecules) and o& ygen 3heavy molecules) gases. A thermometer in the reads !!6C. %hich gas molecules have the greater average speed' A) It is the same for "oth of the gases "ecause the temperatures are the same. B) $he o&ygen molecules do "ecause they are diatomic. C) $he o&ygen molecules do "ecause they are more massive. D) $he helium molecules do "ecause they are less massive. E) $he helium molecules do "ecause they are monatomic. Answer: D ar: 1
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1 7 . 2 Pr o bl e ms 1) A rod has a length !.///// m at 1/./6C. $he length of the rod increases to !.///0/ m when the temperature increases to /./6C. %hat is the coefficient of linear e&pansion of the material from which the rod is made' A) !./ 1/52> B) !.2 1/52> C) 1.2 1/52> D) 1./ 1/5> E) 1./ 1/52> Answer: C ar: 1
!) 7uppose that a steel "ridge* 1/// m long* was "uilt without any e&pansion oints and that only one end of the "ridge was held fi&ed. %hat would the difference in the length of the "ridge "e "etween winter and summer* ta#ing a typical winter temperature as /.//6C* and a typical summer temperature as -/6C' $he coefficient of thermal e&pansion of steel is 1/.2 1/50 51. A) /.-! m B) /.11 mm C) /.11 m D) /.-! mm E) /.9 cm Answer: A ar: 1
) $he e&terior of a supersonic airplane is made of aluminum* which has a coefficient of linear e&pansion of !- 1/50 51. At 126C* the plane measures 0!.1 m in length. %hen the plane is in flight* friction with the air increases the temperature of the e&terior s#in to !//6C. %hat is the change in the length of the outer s#in of the plane' A) !/ cm B) !- cm C) ! cm D) ! cm E) 0 cm Answer: C ar: 1
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-) $wo identical concrete sla"s lie flat and in contact with each other as shown in the figure. If the temperature increases "y -/6C* the lower edge s opposite the contact edges remained fi&ed in position* and the lower edges of the contact side remain in contact* at what angle will the sla"s "e tilted' $he coefficient of thermal e&pansion of the concrete is 1/ 1/50>.
A) 1<6 B) /./!6 C) 126 D) 1.06 E) $he answer depends on the length of the sla"s. Answer: D ar: 1
2) A "rass rod is -/.1 cm long and an aluminum rod is 9<. cm long when "oth rods are at an initial temperature of /6C. $he rods are placed in line with a gap of /.0/ cm "etween them* as shown in the figure. $he distance "etween the far ends of the rods is maintained at 1!/./ cm throughout. $he temperature of "oth rods is raised until the two rods are "arely in contact. $he coefficients of linear e&pansion of "rass and aluminum are !./ 1/52 51 and !.- 1/52 51* respectively. $he temperature at which contact of the rods "arely occurs is closest to
A) !!/6C. B) !1/6C. C) !//6C. D) !/6C. E) !-/6C. Answer: A ar: 1
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0) ou want to insert an aluminum rod* which at !/6C has a radius of 1.///!// cm into a copper tu"e which has a radius of 1.///1// cm at the same temperature. ou decide to put "oth of them in the refrigerator. At what temperature will the rod ust fit if "oth are cooled to the same temperature' $he coefficient of thermal e&pansion for aluminum is !.- 1/52 51* and that of copper is 1.9 1/52 51. A) 9.6C B) 0.6C C) <.!6C D) 126C E) 2.96C Answer: E ar: 1
9) $he hole for a "olt in a "rass plate has a diameter of 1.!// cm at !/6C. %hat is the diameter of the hole when the plate is heated to !!/6C' $he coefficient of linear thermal e&pansion for "rass is 1< 1/50>C6. 3E&press your answer to - significant figures.) A) 1.!/2 cm B) 1.1!2 cm C) 1.1<2 cm D) 1.!// cm E) 1.!1/ cm Answer: A ar: 1
) 1./// @ of water at !/.//6C will occupy what volume if it is heated to /.//6C' %ater has a volume e&pansion coefficient of !1/ 1/50>C6. 3E&press your answer to - significant figures.) A) 1.0// @ B) 1.!0 @ C) 1./1 @ D) /.<9/ @ E) /.<<9 @ Answer: C ar: 1
<) A glass flas# has a volume of 2// m@ at a temperature of !/6C. $he flas# contains of mercury at $he temperature of the mercury and flas# is raised until the mercury reaches the reference mar#. $he coefficients of volume e&pansion of mercury and glass are 1 1/52 51 and !./ 1/52 51* respectively. $he temperature at which this occurs is closest to A) 1!!6C. B) 11!6C. C) 1/!6C. D) 11/6C. E) 1!6C. Answer: A ar: 2/F
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1/) $he coefficient of linear e&pansion of aluminum is !- 1/50 51 and the coefficient of volume e&pansion of olive oil is /.0 1/5 51. A novice coo#* in preparation for deep5frying some potatoes* fills a 1.//5@ aluminum pot to the "rim and heats the oil and the pot from an initial temperature of 126C to 1
11) $he coefficient of volume e&pansion of olive oil is /.0 1/5 51. A 1.//5@ glass "ea#er is filled to the "rim with olive oil at room temperature. $he "ea# er is placed on a range and the temperature of the oil and "ea#er increases "y !2 C6. As a result* /./109 @ of olive oil spill over the top of the "ea#er. %hat is the coefficient of linear e&pansion of the glass' A) 1./ 1/50 51 B) -./ 1/50 51 C) 1./ 1/52 51 D) !./ 1/52 51 E) ./ 1/52 51 Answer: B ar: 1
1!) A certain metal has a coefficient of linear e&pansion of !.// 1/52 51. It has "een #ept in a la"oratory oven at !26C for a long time. It is now removed from the oven and placed in a free,er at 51-26C. After it has reached free,er temperature* the percent change in its density during this process is closest to A) F!.
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1) =eat is added to a pure su"stance in a closed container at a constant rate. $he figure shows a graph of the temperature of the su"stance as a function of time. If Lf 4 latent heat of fusion and Lv 4 latent heat of vapori,ation* what is the value of the ratio Lv > Lf for this su"stance'
A) 2./ B) -.2 C) 9.! D) .2 E) 1.2 Answer: D ar: 1
1-) A su"stance has a melting point of !/6C and a heat of fusion of .< & point is
and the heat of vapori,ation is
H>#g. $he "oiling
at a pressure of 1./ atm. $he
specific heats for the solid* li+uid* and gaseous phases are 0// H>3#g)* 1/// H>3#g)* and -// H>3#g)* respectively. $he +uantity of heat re+uired to raise the temperature of of the su"stance from to at a pressure of 1./ atm* is closest to A) 0!/ #H. B) -9/ #H. C) 20/ #H. D) !1/ #H. E) 99/ #H. Answer: A ar: 2/F
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12) A su"stance has a melting point of !/6C and a heat of fusion of .2 1/- H>#g. $he "oiling point is 12/6C and the heat of vapori,ation is 9./ 1/- H>#g at a pressure of 1./ atm. $he specific heats for the solid* li+uid* and gaseous phases are 0// H>3#g)* 1/// H>3#g)* and -// H>3#g)* respectively. $he +uantity of heat given up "y /.2/ #g of the su"stance when it is cooled from 19/6C to 6C* at a pressure of 1./ atmosphere* is closest to A) 9/ #H. B) 1- #H. C) !1 #H. D) / #H. E) -- #H. Answer: A ar: 1
10) If !./ g of water at /.//6C is to "e vapori,ed* how much heat must "e added to it' $he specific heat of water is 1./ cal>g* its heat of fusion is / cal>g* and its heat of vapori,ation is 2< cal>g. A) 11// cal B) 11// #cal C) 1!// cal D) 1// cal E) 12// cal Answer: D ar: 1
19) If you add 9// #H of heat to 9// g of water at 9/./6C* how much water is left in the container' $he latent heat of vapori,ation of water is !.!0
H>#g and its specific heat is is
-13#g). A) -!< g B) !2 g C) -/ g D) 0// g E) none Answer: A ar: 2
1) =eat is added to a !./ #g piece of ice at a rate of =ow long will it ta#e for the ice to melt if it was initially at /.//6C' 3$he latent heat of fusion for water is - #H>#g and its latent heat of vapori,ation is !!0/ #H>#g.) A) /.- s B) 2/*/// s C) -.9 s D) 09/ s Answer: A ar: 2/F
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1<) A -/0./ #g copper "ar is put into a smelter for melting. $he initial temperature of the copper is //./ . =ow much heat must the smelter produce to completely melt the copper "ar' 3$he specific heat for copper is 0 H>#gJ* the heat of fusion for copper is !/2 #H>#g* and its melting point is 129 .) A) !.-< 1/2 #H B) 1.00 1/11 #H C) 1.00 1/ #H D) !.<0 1/2 #H Answer: A ar: 2/F
!/) $wo e&perimental runs are performed to determine the calorimetric properties of an alcohol that has a melting point of 51/6C. In the first run* a !//5g cu"e of fro,en alcohol* at the melting point* is added to // g of water at !/6C in a styrofoam container. %hen thermal e+uili"rium is reached* the alcohol5water solution is at a temperature of 2./6C. In the second run* an identical cu"e of alcohol is added to 2// g of water at !/6C and the temperature at thermal e+uili"rium is 1/6C. $he specific heat of water is -1#g. Assume that no heat is e&changed with the styrofoam container and with the surroundings. $he heat of fusion of the alcohol is closest to A) 2.2 × 1/- H>#g B) 0. × 1/- H>#g C) 9.1 × 1/- H>#g D) 9.< × 1/- H>#g E) .9 × 1/- H>#g Answer: B ar: 1
!1) $wo e&perimental runs are performed to determine the calorimetric properties of an alcohol that has a melting point of 51/6C. In the first run* a !//5g cu"e of fro,en alcohol* at the melting point* is added to // g of water at !/6C in a styrofoam container. %hen thermal e+uili"rium is reached* the alcohol5water solution is at a temperature of 2./6C. In the second run* an identical cu"e of alcohol is added to 2// g of water at !/6C and the temperature at thermal e+uili"rium is 1/6C. $he specific heat of water is -1#g. Assume that no heat is e&changed with the styrofoam container and with the surroundings. $he specific heat of the alcohol is closest to A) 19// H>#g. B) 1#g. C) !1// H>#g. D) !// H>#g. E) !2// H>#g. Answer: C ar: 1
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!!) A person ma#es ice tea "y adding ice to 1. #g of hot tea* initially at /6C. =ow many #ilograms of ice* initially at /.//6C* are re+uired to " ring the mi&ture to 1/6C' $he heat of fusion of ice is - #H>#g* and we can assume that tea has essentially the same thermal properties as water* so its specific heat is -13#g). A) 1./ #g B) 1.! #g C) 1.- #g D) 1.2 #g E) 1.9 #g Answer: C ar: 1
!) A "loc# of ice at /.///6C is added to a well5insulated 1-95g aluminum calorimeter cup that holds !// g of water at 1/./6C. $he water and aluminum cup are in thermal e+uili"rium* and the specific heat of aluminum is <1/ H>3#g). If all "ut !.// g of ice melt* what was the original mass of the "loc# of ice' $he specific heat of water is -13#g)* its latent heat of fusion is - #H>#g* and its latent heat of vapori,ation is !!0/ #H>#g. A) 1.1 g B) 2.0 g C) . g D) -!./ g E) -9.0 g Answer: A ar: 1
!-) A !//5g metal container* insulated on the outside* holds 1// g of water in thermal e+uili"rium at A !15g ice cu"e* at the melting point* is dropped into the water* and when thermal e+uili"rium is reached the temperature is 12.//6C. Assume there is no heat e&change with the surroundings. ;or water* the specific heat is -1#g and the heat of fusion is .- 1/2 H>#g. $he specific heat for the metal is closest to A) 2/ H>#g . B) !9/ H>#g . C) --2/ H>#g . D) -<2/ H>#g . E) 2-2/ H>#g . Answer: A ar: 2/F
!2) =ow many grams of ice at 516C must "e added to 911 grams of water that is initially at a temperature of to produce water at a final temperature of Assume that no heat is lost to the surroundings and that the container has negligi"le mass. $he specific heat of li+uid water is -1#gC6 and of ice is !/2/ H>#gC6. ;or water the normal melting point is / .//6C and the heat of fusion is - 1/ H>#g. $he normal "oiling point is 1//6C and the heat of vapori,ation is !.!0 1/0 H>#g. Answer: 29/ g ar: 2/F
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!0) $he walls of an ice chest are made of !.//5mm5thic# insulation having a thermal conductivity /.//// %>m. $he total surface area of the ice chest is 1.!/ m!. If -.// #g of ice at /.//6C are placed in the chest and the temperature of the outside surface of the chest is !/./6C* how long does it ta#e the ice to melt under steady state conditions' $he latent heat of fusion of water is 9<.0 cal>g 4 - #H>#g. A) -.!! h B) !!.1 h C) 19.0 h D) 1. d E) 1/. h Answer: E ar: 1
!9) A rod* with sides insulated to prevent heat loss* has one end immersed in "oiling water 1//6C and the other end in a water5ice mi&ture at /.//6C. $he rod has uniform cross5sectional area of and length of melts the ice at a rate of
Knder steady state conditions* the heat conducted "y the rod every - seconds. %hat is the thermal conductivity of the rod'
3$he heat of fusion of water is Answer: !!/ %>m ar: 2/F
!) A spherical o"ect !2./ cm in diameter having an emissivity of /.// is held at a temperature of !926C "y an internal heater. $his o"ect is em"edded in a ve ry large vat of water at 1//./6C and atmospheric pressure. At what ma&imum rate 3in g>min) is the water evaporating in the vat due to the radiated heat it receives from the o"ect' ou can ignore any heat radiated "y the water. $he latent heat of fusion for water is *-// H>#g* its latent heat of vapori,ation is !.! 0 1/0 H>#g* and the 7tefan5Bolt,mann constant is 2.09/ 1/5 %>m! -. Answer: !1. g>min ar: 1
!<) !./ @ of a ideal nitrogen gas 38!) are at /.//6C and 1./ atm. $he ideal gas constant is R 4 .1- H>mol 4 /./!1 @ atm>mol * AvogadroLs num"er is 0./!! 1/! molecules>mol* and the A$(IC mass of nitrogen is 1- g>mol. 3a) Determine the num"er of moles of 8!. 3") =ow many molecules of 8! are present' 3c) %hat is the mass of this gas' Answer: 3a) /./< mol 3") 2.- 1/! molecules 3c) !.2 g ar: 1
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/) If a certain sample of an ideal gas has a temperature of 1/<6C and e&erts a pressure of on the walls of its container* how many gas molecules are present in each cu"ic centimeter of volume' $he ideal gas constant is .1 - H>mol and AvogadroMs num"er is 0./!! 1/! molecules>mol. Answer: !. 1/1 molecules ar: 2/F
1) A vertical tu"e that is closed at the upper end and open at the lower end contains an air poc#et. $he open end of the tu"e is under the water of a la#e* as shown in the figure. %hen the lower end of the tu"e is ust under the surface of the la#e* where the temperature is 96C and the pressure is 1./ 1/2 a* the air poc#et occupies a volume of . 7uppose now that the lower end of the tu"e is at a depth of 0 m in the la#e* where the temperature is 9./6C. %hat is the volume of the air poc#et under these conditions' $he density of the water in the la#e is 1/// #g>m.
Answer: 0/ ar: 2/F
!) A sealed <5
tan# is filled with 0/// moles of o&ygen gas 3!) at an initial temperature of
!9/ . $he gas is heated to a final temperature of 2/ . $he A$(IC mass of o&ygen is 10./ g>mol* and the ideal gas constant is R 4 .1- H>mol 4 /./!1 @ atm>mol . $he initial pressure of the gas is closest to A) /.12 (a. B) /.19 (a. C) /.1< (a. D) /.1 (a. E) /.11 (a. Answer: A ar: 2/F
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) A sealed !05
tan# is filled with !/// moles of o&ygen gas 3!) at an initial temperature of
!9/ . $he gas is heated to a final temperature of -0/ . $he A$(IC mass of o&ygen is 10./ g>mol* and the ideal gas constant is R 4 .1- H>mol 4 /./!1 @ atm>mol . $he final pressure of the gas is closest to A) /.!< (a. B) /.1 (a. C) /. (a. D) /.- (a. E) /.0 (a. Answer: A ar: 2/F
-) A .!5@ volume of neon gas 38e) is at a pressure of . atm and a temperature of / . $he atomic mass of neon is !/.! g>mol* AvogadroLs num"er is 0./!! 1/! molecules>mol* and the ideal gas constant is R 4 .1- H>mol 4 /./!1 @ atm>mol . $he mass of the n eon gas is closest to A) 9.< 1/5 #g. B) -.0 1/5 #g. C) . #g. D) 9. #g. E) 9. 1/! #g. Answer: A ar: 1
2) A weather "alloon contains 1!./ m of hydrogen gas when the "alloon is released from a location at which the temperature is !!./6C and the pressure is 1/1 #a. $he "alloon rises to a location where the temperature is 5/./6C and the pressure is !/./ #a. If the "alloon is free to e&pand so that the pressure of the gas inside is e+ual to the am"ient pressure* what is the new volume of the "alloon' Assume that in "oth cases the hydrogen g as is in thermal e+uili"rium with the outside air. A) 1-./ m B) !. m C) -<.< m D) !.0 m E) -.10 m Answer: C ar: 1
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0) A sealed container holds /./!/ moles of nitrogen 38!) gas* at a pressure of 1.2 atmospheres and a temperature of !mol. $he Bolt,mann constant is 1. 1/5! H> and the ideal gas constant is R 4 .1- H>mol 4 /./!1 @ atm>mol . $he mass density of the gas is closest to A) /.m. B) 1. #g>m. C) 1. #g>m. D) !.! #g>m. E) !.0 #g>m. Answer: C ar: 1
9) An ideal gas is at a pressure 1.// 1/2 8>m! and occupies a volume !.// m. If the gas is compressed to a volume 1.// m while the temperature remains constant* what will "e the new pressure in the gas' A) /.2// 1/2 8>m! B) -.// 1/2 8>m! C) 1.// 1/2 8>m! D) !.// 1/2 8>m! E) $he answer depends on the mass of the gas particles. Answer: D ar: 2
) 7ometimes an e&periment re+uires a certain p ure gas to "e used at reduced pressure. ne way to achieve this is to purchase a sealed glass container filled with the gas* and to introduce the gas into a vacuum "y attaching the glass container to the vacuum cham"er and "rea#ing the tip of the glass container using a metallic "ean and a magnet. If the volume of the glass container is 1./ @ and it is at a pressure of 1./ 1/2 a and if the vacuum cham"er has a volume of !./ @* what will the pressure "e after the gas* which is to "e assumed to "e an ideal gas* is released into the vacuum cham"er and the temperature has returned to its original value' 38ote that the glass container remains part of the system.) A) #a B) 2/ #a C) // #a D) !// #a Answer: A ar: 1
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<) A "ag of potato chips contains !.// @ of air when it is sealed at sea level at a pressure of 1.// atm and a temperature of !/./6C. %hat will "e the volume of the air in the "ag if you ta#e it with you* still sealed* to the mountains where the temperature is 9.//6C and atmospheric pressure is 9/./ #a' Assume that the "ag "ehaves li#e a "alloon and that the air in the "ag is in thermal e+uili"rium with the outside air. 31 atm 4 1./1 1/2 a) A) -.1 @ B) 1./1 @ C) 1. @ D) !.90 @ Answer: D ar: 1
-/) A cold trap is set up to cause molecules to linger near the suction in a vacuum system. If the cold trap has an effective volume of /.!// @ and is maintained at how many molecules are in it at 1/./ a of pressure' 3AvogadroMs num"er is 0./!! 1/! molecules>mol* and the universal gas constant is .1- H>molJ. Assume the "ehavior of an ideal gas.) A) 1.11 × 1/1< molecules B) 1.1/ × 1/!! molecules C) 9.91 × 1/!/ molecules D) 9.91 × 1/! molecules Answer: A ar: 2
-1) A hot air "alloon has a volume of !.// 1/ m when fully inflated* and the air inside the "alloon is always at atmospheric pressure of 1./1 1/2 a "ecause of the large opening used to fill the "alloon and heat the air inside it. %hat is the mass of hot air inside the "alloon if its temperature is 1!/6C' $he universal gas constant is .1- H>molJ. 3Assume a molecular weight of !. g>mol for air.) A) 19/ #g B) 22/ #g C) !/ #g D) 0!./ #g Answer: A ar: 1
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-!) $he figure shows a 2/5#g frictionless cylindrical piston that floats on /.0 mol of compressed air at /6C. =ow far does the piston move if the temperature is increased to //6C'
A) 1!/ cm B) !2/ cm C) 1/ cm D) 1// cm Answer: A ar: 2/F
-) .// moles of an ideal gas at a pressure of !2/ #a are held in a container of volume of !2./ @. $he ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol * and 1 atm 4 1./1 & 1/2 a. $he temperature of this gas is closest to A) !-/6C. B) 51/6C. C) -/6C. D) 51./6C. E) 5!!6C. Answer: E ar: 1
--) =ow many moles of water 3=!) molecules are in a -.// m container at a pressure .// 1/2 8>m! and temperature 0//6C' $he ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol . A) 9.9! 1/!0 mol B) 0-1 mol C) --1 mol D) .0 1/!0 mol E) !.02 1/!0 mol Answer: C ar: 1
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-2) $he interior of a refrigerator has a volume of /.0// m. $he temperature inside the refrigerator in !! * and the pressure is 1/1 #a. If the molecular weight of air is !< g>mol* what is the mass of air inside the refrigerator' $he ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol . A) 2// g B) 20/ g C) 1-/ g D) !9/ g E) 92/ g Answer: E ar: 1
-0) %hat is the mass density of argon gas at pressure 1.// 1/2 8>m! and at temperature // ' $he mean atomic mass of argon is <.<- g>mol and the ideal gas constant is R 4 .1H>molJ 4 /./!1 @ atm>mol . A) 1.-/ #g>m B) 1.// #g>m C) 1.!/ #g>m D) 1.0/ #g>m E) 1./ #g>m Answer: D ar: 1
-9) A !25@ container holds ideal hydrogen 3=!) gas at a gauge pressure of /.!2 atm and a temperature of /6C. %hat mass of hydrogen gas is in this container' $he A$(IC mass of hydrogen is 1./ g>mol* the ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol * and 1.// atm 4 1/1 #a. A) 1.- g B) !. g C) -.! g D) 2.0 g E) 0. g Answer: B ar: 1
-) %hat is the total translational #inetic energy in a test cham"er filled with nitrogen 38!) at and
$he dimensions of the cham"er are
$he
A$(IC weight of nitrogen is !./ g>mol* AvogadroLs num"er is 0./!! 1/! molecules>mol and the Bolt,mann constant is 1. 1/5! H>. Answer: 2.-9 1/9 H ar: 2/F
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-<) A 2./5liter gas tan# holds 1.- moles of helium 3=e) and /.9/ moles of o&ygen 3!)* at a temperature of !0/ . $he atomic masses of helium and o&ygen are -./ g>mol and 10./ g>mol* respectively. AvogadroLs num"er is 0./!! 1/! molecules>mol and the Bolt,mann constant is 1. 1/5! H>. $he total random translational #inetic energy of the gas in the tan# is closest to A) 0. #H. B) 0.1 #H. C) 9.0 #H. D) . #H. E) <.1 #H. Answer: A ar: 1
2/) A 2./5liter gas tan# holds 1.9 moles of monatomic helium 3=e) and 1.1/ mole of diatomic o&ygen 3!)* at a temperature of !0/ . $he A$(IC masses of helium and o&ygen are -./ g>mol and 10./ g>mol* respectively. %hat is the ratio of the root5mean5s+uare 3thermal) speed of helium to that of o&ygen' A) 1.B) !./ C) !. D) -./ E) 2.0 Answer: C ar: 2/F
21) An ideal gas is #ept in a rigid container that e&pan ds negligi"ly when heated. $he gas starts at a temperature of !/./6C* and heat is added to increase its temperature. At what temperature will its root5mean5s+uare speed 3thermal speed) "e dou"le its value at !/./6C' A) -/./6C B) 1-16C C) 16C D) -//6C E) <<6C Answer: E ar: 1
2!) $he root5mean5s+uare speed 3thermal speed) for a certain gas at 1//6C is /.2// #m>s. If the temperature of the gas is now increased to !//6C* the root5mean5s+uare 3thermal) speed will "e closest to A) 20 m>s. B) 0- m>s. C) 9/9 m>s. D) /- m>s. E) 1/// m>s. Answer: A ar: 1
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2) A /.1/5
gas tan# holds 2./ moles of nitrogen gas 38!)* at a temperature of $he atomic mass of nitrogen is 1- g>mol* the molecular radius is ./ 1/ 51/ m* and the Bolt,mann constant is 1. 1/5! H>. $he root5mean5s+uare speed 3thermal speed) of the molecules is closest to A) 29/ m>s. B) 1/ m>s. C) -1/ m>s. D) !! m>s. E) << m>s. Answer: A ar: 2/F
2-) %hat is the average translational #inetic energy per molecule of an ideal gas at a temperature of // ' $he Bolt,mann constant is 1. 1/5! H>. A) 1.9 1/5!1 H B) . 1/5!1 H C) 0.! 1/5!1 H D) !.1 1/5!1 H E) -.1 1/5!1 H Answer: C ar: 1
22) $he root5mean5s+uare speed 3thermal speed) of a certain sample of car"on dio&ide molecules* with a molecular weight of -- g>mol* is <0 m>s. %hat is the root5mean5s+uare speed 3thermal speed) of water vapor molecules* with a molecular we ight of 1 g>mol* at the same temperature' A) !2 m>s B) <0 m>s C) -!1 m>s D) 2/0 m>s E) 01< m>s Answer: E ar: 1
20) $he root5mean5s+uare speed 3thermal speed) of the molecules of a gas is !// m>s at a temperature !./6C. %hat is the mass of the individual molecules' $he Bolt,mann constant is 1. 1/5! H>. A) !.1 1/5!2 #g B) !.-2 1/5!2 #g C) 2.00 1/5!2 #g D) 1.9 1/5!2 #g E) .11 1/5!2 #g Answer: E ar: 1
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29) A sealed container holds /./!/ moles of nitrogen 38!) gas at a pressure of 1.2 atmospheres and a temperature of !mol. $he Bolt,mann constant is 1. 1/5! H> and the ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol . $he average translational #inetic energy of a nitrogen molecule is c losest to A) -./ × 1/5!1 H. B) 0./ × 1/5!1 H. C) ./ × 1/5!1 H. D) 1/ × 1/5!1 H. E) 1! × 1/5!1 H. Answer: B ar: 1
2) At 2/./6C* the average translational #inetic energy of a gas molecule is K . If the temperature is now increased to 1//./6C* the average translational #inetic energy of a molecule will "e closest to A) 1./9 K. B) 1.12 K. C) 1.-1 K. D) !.// K. E) -.// K. Answer: B ar: 1
2<) $he root5mean5s+uare speed 3thermal speed) of the molecules of a gas is !// m>s at !./6C. At !!96C the root5mean5s+uare speed 3thermal speed) of the molecules will "e closest to A) 10/ m>s B) / m>s C) !0/ m>s D) 0/ m>s E) !/// m>s Answer: C ar: 1
0/) A cu"ic "o& with sides of !/./ cm contains !.// 1/! molecules of helium with a root5 mean5s+uare speed 3thermal speed) of !// m>s. $he mass of a helium molecule is .-/ 1/5!9 #g. %hat is the average pressure e&erted "y the molecules on the walls of the container' $he Bolt,mann constant is 1. 1/5! H> and the ideal gas constant is R 4 .1- H>molJ 4 /./!1 @ atm>mol . A) .< #a B) 1.1 #a C) 29/ a D) !.!0 #a E) <.1/ a Answer: B ar: 1
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01) At what temperature would the root5mean5s+uare speed 3thermal speed) of o&ygen molecules "e 1./ m>s' Assume that o&ygen appro&imates an ideal gas. $he mass of one ! molecule is 2.1! & 1/5!0 #g. $he Bolt,mann constant is 1. 1/5! H>. A) /.!19 B) 1// C) 2-1/ D) /./000 Answer: A ar: 1
0!) %hat is the average #inetic energy of an ideal gas molecule at 20<6C' 3$he Bolt,mann constant is 1. 1/5! H>.) A) 1.9- 1/5!/ H B) 2.1 1/5!1 H C) 1.1 1/519 H D) .< 1/51< H Answer: A ar: 1
0) Dust particles are pulveri,ed roc#* which has density !2// #g>m. $hey are appro&imately spheres !/ μm in diameter. $reating dust as an ideal gas* what is the root5mean5s+uare speed 3thermal speed) of a dust particle at 3$he Bolt,mann constant is 1. 1/5! H>.) A) 2.! 1/52 m>s B) 1.9 1/52 m>s C) ./ 1/52 m>s D) 9. 1/52 m>s Answer: A ar: 2/F
0-) An o&ygen molecule falls in a vacuum. ;rom what height must it fall so that its #inetic energy at the "ottom e+uals the average energy of an o&ygen molecule at // ' 3$he Bolt,mann constant is 1. 1/5! H>* the molecular weight of o&ygen is !./ g>mol* and AvogadroLs num"er is 0./!! 1/! molecules>mol.) A) 1. #m B) 1/.0 #m C) !1.1 #m D) -!. #m Answer: A ar: 1
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