Question 1

In which process is ΔH = ΔU?

Accepted Answer

A)  Two moles of ammonia gas are cooled from 325°C to 300°C at a constant pressure of 1.2 atm.
B)  One gram of water is vaporized at 100°C and 1 atm.
C)  Two moles of hydrogen iodide gas react to form hydrogen gas and iodine gas in a 40-L container.
D)  Solid calcium carbonate is heated to form solid calcium oxide and carbon dioxide gas in a container with variable volume.
E)  One mole of solid carbon dioxide sublimes to the gas phase.F) B) and E)
G) D) and E)

Question 2

If 325 g of water at 4.2°C absorbs 12.28 kJ,what is the final temperature of the water? The specific heat of water is 4.184 J/g·°C.

Accepted Answer

A)  4.21°C
B)  4.8°C
C)  9.0°C
D)  13.2°C
E)  2938°CF) A) and C)
G) All of the above

Question 3

A 307-g sample of an unknown mineral was heated to 98.7°C and placed into a calorimeter containing 72.4 g of water at 23.6°C.The heat capacity of the calorimeter was 15.7 J/°C.The final temperature in the calorimeter was 32.4°C.What is the specific heat capacity of the mineral?

Accepted Answer

A)  0.124 J/g·°C
B)  0.131 J/g·°C
C)  0.138 J/g·°C
D)  0.145 J/g·°C
E)  None of these choices is correct.F) A) and C)
G) C) and D)

Question 4

What is the standard enthalpy change for the decomposition of one mole of SO3? 2SO2 + O2→ 2SO3 ΔH°rxn = -198 kJ/mol

Accepted Answer

A)  198 kJ/mol
B)  -99.0 kJ/mol
C)  99.0 kJ/mol
D)  396 kJ/mol
E)  -396 kJ/molF) C) and D)
G) All of the above

Question 5

A(n)___________ __________ is a process where heat is absorbed from the surroundings.

Accepted Answer

endothermic process

Question 6

If 75.4 J of energy is absorbed by 0.25 mol of CCl4 at constant pressure,what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

Accepted Answer

A)  17.8°C
B)  21.9°C
C)  2.3°C
D)  9.1°C
E)  44.6°CF) C) and D)
G) B) and D)

Question 7

Atoms A and Z may form either single bonds or double bonds.Shown is an energy diagram for the formation of a single bond between A and Z from the individual atoms in the gas phase.  Which diagram below corresponds to the reaction A(g) + Z(g) → A=Z(g) ?

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) B) and D)
G) B) and C)

Question 8

What is the change in temperature if a 25.0-g block of aluminum absorbs 10.0 kJ of heat? The specific heat of aluminum is 0.900 J/g·°C.

Accepted Answer

A)  0.44°C
B)  22.5°C
C)  225°C
D)  360°C
E)  444°CF) C) and D)
G) B) and E)

Question 9

What is ΔH°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide? CaCO3(s) → CaO(s) + CO2(g) 
Substance ΔH°f(kJ/mol) 
CaCO3(s) -1206.9
CaO(s) -635.6
CO2(g) -393.5

Accepted Answer

A)  -2236.0 kJ/mol
B)  -1449.0 kJ/mol
C)  -177.8 kJ/mol
D)  177.8 kJ/mol
E)  2236.0 kJ/molF) A) and E)
G) B) and D)

Question 10

The enthalpy of formation of a liquid is always larger than the enthalpy of formation of the gas of the same compound.

Accepted Answer

A) True 
 B)False

Question 11

Styrene,C8H8,is one of the substances used in the production of synthetic rubber.When styrene burns in oxygen to form carbon dioxide and liquid water under standard-state conditions at 25°C,42.15 kJ are released per gram of styrene.Find the standard enthalpy of formation of styrene at 25°C. ΔH°f(CO2(g) ) = -393.5 kJ/mol,ΔH°f(H2O(l) ) = -285.8 kJ/mol

Accepted Answer

A)  -4390 kJ/mol
B)  -1044 kJ/mol
C)  -8681 kJ/mol
D)  +99 kJ/mol
E)  +637 kJ/molF) B) and D)
G) A) and E)

Question 12

A system receives 575 J of heat and delivers 424 J of work.What is the change in the internal energy,ΔU,of the system?

Accepted Answer

A)  -150.J
B)  150.J
C)  -1000.J
D)  1000.J
E)  575 JF) A) and E)
G) A) and C)

Question 13

Naphthalene combustion may be used to calibrate the heat capacity of a bomb calorimeter.The heat of combustion of naphthalene is -40.1 kJ/g.When 0.8210 g of naphthalene was burned in a bomb calorimeter containing 1.000 kg of water,a temperature rise of 4.21°C was observed.What is the heat capacity of the bomb calorimeter excluding the water?

Accepted Answer

A)  32.9 kJ/°C
B)  7.8 kJ/°C
C)  3.64 kJ/°C
D)  1.76 kJ/°C
E)  15.3 kJ/°CF) A) and C)
G) B) and C) C

Question 14

___________ is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.
pecific heat

Accepted Answer

The answer of ___________ is the amount of heat required...

Question 15

How much heat is required to raise the temperature of 22.8 g of copper from 20.0°C to 875.0°C? The specific heat of copper is 0.385 J/g·°C.

Accepted Answer

A)  14.4 J
B)  176 J
C)  7.51 kJ
D)  7.68 kJ
E)  9.90 kJF) A) and B)
G) A) and E)

Question 16

A 275-g sample of nickel at l00.0°C is placed in 100.0 g of water at 22.0°C.What is the final temperature of the water? Assume no heat transfer with the surroundings.The specific heat of nickel is 0.444 J/g·°C and the specific heat of water is 4.184 J/g·°C.

Accepted Answer

A)  39.6°C
B)  40.8°C
C)  61.0°C
D)  79.2°C
E)  82.4°CF) A) and E)
G) A) and B)

Question 17

In which reaction would you expect ΔH to be substantially greater than ΔU (i.e.,ΔH > ΔU) ?

Accepted Answer

A)  H2(g) + Br2(g) → 2HBr(g) 
B)  CO2(s) → CO2(g) 
C)  C2H2(g) + H2(g) → C2H4(g) 
D)  H2O(s) → H2O(l) 
E)  HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) F) A) and B)
G) A) and E)

Question 18

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide according to the following balanced chemical equation.What is ΔH°rxn for this reaction? 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) 
Substance ΔH°f(kJ/mol) 
NH3(g) -46.3
NO(g) 90.3
H2O(g) -241.8

Accepted Answer

A)  -1274.8 kJ/mol
B)  -904.4 kJ/mol
C)  -240.2 kJ/mol
D)  -197.8kJ
E)  197.8 kJ/molF) A) and B)
G) B) and C)

Question 19

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134-g sample of NH4Cl is added to 65.0 mL of water in a calorimeter at 24.5°C,what is the final temperature of the solution? The specific heat of water is 4.18 J/g·°C and the heat capacity of the calorimeter is 365 J/°C.

Accepted Answer

A)  27.1°C
B)  18.6°C
C)  19.7°C
D)  21.8°C
E)  30.4°CF) A) and E)
G) None of the above D

Question 20

Aluminum oxide can be reduced to aluminum metal using carbon,the other reaction product being carbon monoxide.What is the enthalpy change if 12.50 g of aluminum is produced by this method? Substance ΔH°f(kJ/mol) 
CO(g) -110.5
Al2O3(s) -1669.8

Accepted Answer

A)  310.0 kJ
B)  386.8 kJ
C)  412.4 kJ
D)  773.6 kJ
E)  824.8 kJF) D) and E)
G) B) and D)

Exam 5: Thermochemistry

In which process is ΔH = ΔU?

Correct Answer
verified

If 325 g of water at 4.2°C absorbs 12.28 kJ,what is the final temperature of the water? The specific heat of water is 4.184 J/g·°C.

Correct Answer
verified

A 307-g sample of an unknown mineral was heated to 98.7°C and placed into a calorimeter containing 72.4 g of water at 23.6°C.The heat capacity of the calorimeter was 15.7 J/°C.The final temperature in the calorimeter was 32.4°C.What is the specific heat capacity of the mineral?

Correct Answer
verified

What is the standard enthalpy change for the decomposition of one mole of SO₃? 2SO₂ + O₂→ 2SO₃ ΔH°_rxn = -198 kJ/mol

Correct Answer
verified

A(n)_ is a process where heat is absorbed from the surroundings.

Correct Answer
verified
endothermic process

If 75.4 J of energy is absorbed by 0.25 mol of CCl₄ at constant pressure,what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

Correct Answer
verified

Atoms A and Z may form either single bonds or double bonds.Shown is an energy diagram for the formation of a single bond between A and Z from the individual atoms in the gas phase. Which diagram below corresponds to the reaction A(g) + Z(g) → A=Z(g) ?

Correct Answer
verified

What is the change in temperature if a 25.0-g block of aluminum absorbs 10.0 kJ of heat? The specific heat of aluminum is 0.900 J/g·°C.

Correct Answer
verified

What is ΔH°_rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide? CaCO₃(s) → CaO(s) + CO₂(g) Substance ΔH°_f(kJ/mol) CaCO₃(s) -1206.9 CaO(s) -635.6 CO₂(g) -393.5

Correct Answer
verified

The enthalpy of formation of a liquid is always larger than the enthalpy of formation of the gas of the same compound.

Correct Answer
verified

Correct Answer
verified

A system receives 575 J of heat and delivers 424 J of work.What is the change in the internal energy,ΔU,of the system?

Correct Answer
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Correct Answer
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C

___________ is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. pecific heat

Correct Answer
verified

How much heat is required to raise the temperature of 22.8 g of copper from 20.0°C to 875.0°C? The specific heat of copper is 0.385 J/g·°C.

Correct Answer
verified

A 275-g sample of nickel at l00.0°C is placed in 100.0 g of water at 22.0°C.What is the final temperature of the water? Assume no heat transfer with the surroundings.The specific heat of nickel is 0.444 J/g·°C and the specific heat of water is 4.184 J/g·°C.

Correct Answer
verified

In which reaction would you expect ΔH to be substantially greater than ΔU (i.e.,ΔH > ΔU) ?

Correct Answer
verified

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide according to the following balanced chemical equation.What is ΔH°_rxn for this reaction? 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) Substance ΔH°_f(kJ/mol) NH₃(g) -46.3 NO(g) 90.3 H₂O(g) -241.8

Correct Answer
verified

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134-g sample of NH₄Cl is added to 65.0 mL of water in a calorimeter at 24.5°C,what is the final temperature of the solution? The specific heat of water is 4.18 J/g·°C and the heat capacity of the calorimeter is 365 J/°C.

Correct Answer
verified
D

Aluminum oxide can be reduced to aluminum metal using carbon,the other reaction product being carbon monoxide.What is the enthalpy change if 12.50 g of aluminum is produced by this method? Substance ΔH°_f(kJ/mol) CO(g) -110.5 Al₂O₃(s) -1669.8

Correct Answer
verified

Exam 5: Thermochemistry

In which process is ΔH = ΔU?

Correct AnswerverifiedShow Answer

If 325 g of water at 4.2°C absorbs 12.28 kJ,what is the final temperature of the water? The specific heat of water is 4.184 J/g·°C.

Correct AnswerverifiedShow Answer

A 307-g sample of an unknown mineral was heated to 98.7°C and placed into a calorimeter containing 72.4 g of water at 23.6°C.The heat capacity of the calorimeter was 15.7 J/°C.The final temperature in the calorimeter was 32.4°C.What is the specific heat capacity of the mineral?

Correct AnswerverifiedShow Answer

What is the standard enthalpy change for the decomposition of one mole of SO3? 2SO2 + O2→ 2SO3 ΔH°rxn = -198 kJ/mol

Correct AnswerverifiedShow Answer

A(n)___________ __________ is a process where heat is absorbed from the surroundings.

Correct Answerverifiedendothermic process

If 75.4 J of energy is absorbed by 0.25 mol of CCl4 at constant pressure,what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

Correct AnswerverifiedShow Answer

Atoms A and Z may form either single bonds or double bonds.Shown is an energy diagram for the formation of a single bond between A and Z from the individual atoms in the gas phase. Which diagram below corresponds to the reaction A(g) + Z(g) → A=Z(g) ?

Correct AnswerverifiedShow Answer

What is the change in temperature if a 25.0-g block of aluminum absorbs 10.0 kJ of heat? The specific heat of aluminum is 0.900 J/g·°C.

Correct AnswerverifiedShow Answer

What is ΔH°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide? CaCO3(s) → CaO(s) + CO2(g) Substance ΔH°f(kJ/mol) CaCO3(s) -1206.9 CaO(s) -635.6 CO2(g) -393.5

Correct AnswerverifiedShow Answer

The enthalpy of formation of a liquid is always larger than the enthalpy of formation of the gas of the same compound.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A system receives 575 J of heat and delivers 424 J of work.What is the change in the internal energy,ΔU,of the system?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedC

___________ is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. pecific heat

Correct AnswerverifiedShow Answer

How much heat is required to raise the temperature of 22.8 g of copper from 20.0°C to 875.0°C? The specific heat of copper is 0.385 J/g·°C.

Correct AnswerverifiedShow Answer

A 275-g sample of nickel at l00.0°C is placed in 100.0 g of water at 22.0°C.What is the final temperature of the water? Assume no heat transfer with the surroundings.The specific heat of nickel is 0.444 J/g·°C and the specific heat of water is 4.184 J/g·°C.

Correct AnswerverifiedShow Answer

In which reaction would you expect ΔH to be substantially greater than ΔU (i.e.,ΔH > ΔU) ?

Correct AnswerverifiedShow Answer

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide according to the following balanced chemical equation.What is ΔH°rxn for this reaction? 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) Substance ΔH°f(kJ/mol) NH3(g) -46.3 NO(g) 90.3 H2O(g) -241.8

Correct AnswerverifiedShow Answer

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134-g sample of NH4Cl is added to 65.0 mL of water in a calorimeter at 24.5°C,what is the final temperature of the solution? The specific heat of water is 4.18 J/g·°C and the heat capacity of the calorimeter is 365 J/°C.

Correct AnswerverifiedD

Aluminum oxide can be reduced to aluminum metal using carbon,the other reaction product being carbon monoxide.What is the enthalpy change if 12.50 g of aluminum is produced by this method? Substance ΔH°f(kJ/mol) CO(g) -110.5 Al2O3(s) -1669.8

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is the standard enthalpy change for the decomposition of one mole of SO₃? 2SO₂ + O₂→ 2SO₃ ΔH°_rxn = -198 kJ/mol

Correct Answer
verified

A(n)_ is a process where heat is absorbed from the surroundings.

Correct Answer
verified
endothermic process

If 75.4 J of energy is absorbed by 0.25 mol of CCl₄ at constant pressure,what is the change in temperature? The specific heat of CCl4 is 0.861 J/g·°C.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is ΔH°_rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide? CaCO₃(s) → CaO(s) + CO₂(g) Substance ΔH°_f(kJ/mol) CaCO₃(s) -1206.9 CaO(s) -635.6 CO₂(g) -393.5

Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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C

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide according to the following balanced chemical equation.What is ΔH°_rxn for this reaction? 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) Substance ΔH°_f(kJ/mol) NH₃(g) -46.3 NO(g) 90.3 H₂O(g) -241.8

Correct Answer
verified

The heat of solution of ammonium chloride is 15.2 kJ/mol.If a 6.134-g sample of NH₄Cl is added to 65.0 mL of water in a calorimeter at 24.5°C,what is the final temperature of the solution? The specific heat of water is 4.18 J/g·°C and the heat capacity of the calorimeter is 365 J/°C.

Correct Answer
verified
D

Aluminum oxide can be reduced to aluminum metal using carbon,the other reaction product being carbon monoxide.What is the enthalpy change if 12.50 g of aluminum is produced by this method? Substance ΔH°_f(kJ/mol) CO(g) -110.5 Al₂O₃(s) -1669.8

Correct Answer
verified