Question 1

If two solutions are mixed together in a container and the container "feels hot",then

Accepted Answer

A)  the reaction is endothermic.
B)  the reaction is exothermic.
C)  the energy of the universe is increased.
D)  the energy of both the system and the surroundings is decreased.
E)  the energy of the system is increased.F) None of the above
G) A) and D)

Question 2

What is ΔH°rxn for the following reaction? SiO2(s) + 4HCl(g) → SiCl4(g) + 2H2O(g) 
Substance ΔH°f(kJ/mol) 
SiO2(s) -859.3
SiCl4(g) -662.8
HCl(g) -92.3
H2O(g) -241.8

Accepted Answer

A)  -1856.2 kJ/mol
B)  -1372.6 kJ/mol
C)  -47.0 kJ/mol
D)  82.1 kJ/mol
E)  530.6 kJ/molF) A) and B)
G) A) and E)

Question 3

Which is not a state function?

Accepted Answer

A)  internal energy
B)  volume
C)  work
D)  pressure
E)  enthalpyF) B) and C)
G) A) and B)

Question 4

For which reaction is ΔH approximately (or exactly) equal to ΔU?

Accepted Answer

A)  H2(g) + Br2(g) → 2HBr(g) 
B)  H2O(l) → H2O(g) 
C)  CaCO3(s) → CaO(s) + CO2(g) 
D)  2H(g) + O(g) → H2O(l) 
E)  CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) F) D) and E)
G) A) and E)

Question 5

A student used a bomb calorimeter to determine the heat of combustion of an unknown compound.If the student ignored the heat capacity of the bomb calorimeter,the heat capacity of the unknown compound would be _________ the accepted value.

Accepted Answer

A)  greater than (i.e.,less negative) 
B)  less than (i.e.,more negative) 
C)  equal toD) None of the above
E) A) and B)

Question 6

The combustion of pentane produces heat according to the following thermochemical equation. C5H12(l) + 8O2(g) → 5CO2(g) + 6H2O(l) ΔH°rxn = -3510 kJ/mol
How many grams of CO2 is produced per 2.50 × 103 kJ of heat released?

Accepted Answer

A)  6.27 g
B)  31.3 g
C)  61.8 g
D)  157 g
E)  220 gF) A) and B)
G) A) and C)

Question 7

Your favorite candy bar,Gummy Beakers,contains 1.2 × 106 J of energy while your favorite soft drink,Bolt,contains 6.7 × 105 J.If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt,what percent of your 2000 Calorie daily food intake is left for broccoli,beans,beef,etc.? (1 cal = 4.184 J)

Accepted Answer

A)  53%
B)  47%
C)  27%
D)  11%
E)  0%F) A) and B)
G) All of the above

Question 8

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,U,is 61.2 kJ,what is the final value of U?

Accepted Answer

A)  32.7 kJ
B)  46.5 kJ
C)  61.2 kJ
D)  75.9 kJ
E)  89.7 kJF) A) and D)
G) C) and E)

Question 9

What is ΔH°rxn for the following reaction? NO2(g) + CO(g) → CO2(g) + NO(g) 
Substance ΔH°f(kJ/mol) 
NO(g) +90.4
NO2(g) +33.85
CO(g) -110.5
CO2(g) -393.5

Accepted Answer

A)  339.6 kJ
B)  379.8 kJ
C)  -226.5 kJ
D)  -339.6 kJ
E)  -379.8 kJF) A) and D)
G) A) and C)

Question 10

How much heat is released if 7.15 g CaO(s) is added to 152 g of H2O(l) ? CaO(s) + H2O(l) → Ca(OH) 2(s) ΔH°rxn = -64.8 kJ/mol

Accepted Answer

A)  7.68 kJ
B)  8.26 kJ
C)  508 kJ
D)  547 kJ
E)  555 kJF) A) and E)
G) B) and E)

Question 11

A system delivers 1275 J of heat while the surroundings perform 854 J of work on it.What is ΔU of the system?

Accepted Answer

A)  -2129 J
B)  -421 J
C)  +421 J
D)  +2129 J
E)  -1275 JF) A) and D)
G) B) and E)

Question 12

Chemical reactions in a bomb calorimeter occur at constant pressure.

Accepted Answer

A) True 
 B)False

Question 13

For which of the substances below is ΔHof = 0?

Accepted Answer

A)  O2(g) 
B)  N2(l) 
C)  Na(g) 
D)  Xe(l) 
E)  A and BF) B) and E)
G) All of the above

Question 14

Consider the following two representations of chemical reactions.Each sphere represents 1 mol of atoms. rxn for the following reaction? CS(g) + O(g) → CO(g) + S(g)  A) -359 kJ/mol B) 1434 kJ/mol C) -7142 kJ/mol D) -1434 kJ/mol E) 7142 kJ/mol" class="answers-bank-image d-inline" rel="preload" > What is ΔHºrxn for the following reaction? CS(g) + O(g) → CO(g) + S(g)

Accepted Answer

A)  -359 kJ/mol
B)  1434 kJ/mol
C)  -7142 kJ/mol
D)  -1434 kJ/mol
E)  7142 kJ/molF) A) and E)
G) B) and C)

Question 15

What law states that energy can be converted from one form to another,but cannot be created or destroyed?

Accepted Answer

A)  universal law
B)  first law of thermodynamics
C)  law of mass conservation
D)  law of conservation of energy
E)  law of constant energyF) A) and C)
G) A) and D)

Question 16

The dissolution of barium hydroxide in water is an exothermic process.Which statement is correct?

Accepted Answer

A)  The enthalpy of solid barium hydroxide plus pure water is less than that of the solution,at the same temperature.
B)  The enthalpy of solid barium hydroxide plus pure water is greater than that of the solution,at the same temperature.
C)  The enthalpy of solid barium hydroxide plus pure water is the same as that of the solution,at the same temperature.
D)  The temperature of the solution is lower than of the barium hydroxide and water before mixing.
E)  When barium hydroxide dissolves in water,the system does work on the surroundings.F) B) and D)
G) A) and D)

Question 17

A glass containing 200.0 g of H2O at 20.0°C was placed in a refrigerator.The water loses 11.7 kJ as it cools to a constant temperature.What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Accepted Answer

A)  0.0°C
B)  4.0°C
C)  6.0°C
D)  14.0°C
E)  34.0°CF) A) and B)
G) C) and D)

Question 18

An endothermic reaction causes the surroundings to

Accepted Answer

A)  warm up.
B)  become acidic.
C)  condense.
D)  decrease in temperature.
E)  release CO2.F) A) and C)
G) C) and E)

Question 19

Two solutions (the system) ,each with a volume of 25.0 mL at 25.0°C,are mixed in a beaker.A reaction occurs between them,and the temperature rises to 35.0°C.After the products have equilibrated with the surroundings,the temperature is again 25.0°C and the total volume is 50.0 mL.No gases are involved in the reaction.Which relationship concerning the change from initial to final states (both at 25.0°C) is correct?

Accepted Answer

A)  ΔU = 0
B)  ΔH = 0
C)  ΔU > 0
D)  q = 0
E)  W = 0F) A) and B)
G) C) and D)

Question 20

When 0.7521 g of benzoic acid was burned in a calorimeter containing 1000.g of water,a temperature rise of 3.60°C was observed.What is the heat capacity of the bomb calorimeter,excluding the water? The heat of combustion of benzoic acid is -26.42 kJ/g.

Accepted Answer

A)  15.9 kJ/°C
B)  4.2 kJ/°C
C)  5.5 kJ/°C
D)  1.3 kJ/°C
E)  752 kJ/°CF) A) and B)
G) All of the above

Exam 5: Thermochemistry

What law states that energy can be converted from one form to another,but cannot be created or destroyed?

Correct Answer
verified

When 0.7521 g of benzoic acid was burned in a calorimeter containing 1000.g of water,a temperature rise of 3.60°C was observed.What is the heat capacity of the bomb calorimeter,excluding the water? The heat of combustion of benzoic acid is -26.42 kJ/g.

Correct Answer
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A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,U,is 61.2 kJ,what is the final value of U?

Correct Answer
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Correct Answer
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Chemical reactions in a bomb calorimeter occur at constant pressure.

Correct Answer
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Which is not a state function?

Correct Answer
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For which of the substances below is ΔH^o_f = 0?

Correct Answer
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What is ΔH°_rxn for the following reaction? SiO₂(s) + 4HCl(g) → SiCl₄(g) + 2H₂O(g) Substance ΔH°_f(kJ/mol) SiO₂(s) -859.3 SiCl₄(g) -662.8 HCl(g) -92.3 H₂O(g) -241.8

Correct Answer
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If two solutions are mixed together in a container and the container "feels hot",then

Correct Answer
verified

A glass containing 200.0 g of H₂O at 20.0°C was placed in a refrigerator.The water loses 11.7 kJ as it cools to a constant temperature.What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Correct Answer
verified

Correct Answer
verified

Consider the following two representations of chemical reactions.Each sphere represents 1 mol of atoms. What is ΔHº_rxn for the following reaction? CS(g) + O(g) → CO(g) + S(g)

Correct Answer
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For which reaction is ΔH approximately (or exactly) equal to ΔU?

Correct Answer
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An endothermic reaction causes the surroundings to

Correct Answer
verified

The dissolution of barium hydroxide in water is an exothermic process.Which statement is correct?

Correct Answer
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The combustion of pentane produces heat according to the following thermochemical equation. C₅H₁₂(l) + 8O₂(g) → 5CO₂(g) + 6H₂O(l) ΔH°_rxn = -3510 kJ/mol How many grams of CO₂ is produced per 2.50 × 10³ kJ of heat released?

Correct Answer
verified

A system delivers 1275 J of heat while the surroundings perform 854 J of work on it.What is ΔU of the system?

Correct Answer
verified

A student used a bomb calorimeter to determine the heat of combustion of an unknown compound.If the student ignored the heat capacity of the bomb calorimeter,the heat capacity of the unknown compound would be _________ the accepted value.

Correct Answer
verified

How much heat is released if 7.15 g CaO(s) is added to 152 g of H₂O(l) ? CaO(s) + H₂O(l) → Ca(OH) ₂(s) ΔH°_rxn = -64.8 kJ/mol

Correct Answer
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What is ΔH°_rxn for the following reaction? NO₂(g) + CO(g) → CO₂(g) + NO(g) Substance ΔH°_f(kJ/mol) NO(g) +90.4 NO₂(g) +33.85 CO(g) -110.5 CO₂(g) -393.5

Correct Answer
verified

Exam 5: Thermochemistry

What law states that energy can be converted from one form to another,but cannot be created or destroyed?

Correct AnswerverifiedShow Answer

When 0.7521 g of benzoic acid was burned in a calorimeter containing 1000.g of water,a temperature rise of 3.60°C was observed.What is the heat capacity of the bomb calorimeter,excluding the water? The heat of combustion of benzoic acid is -26.42 kJ/g.

Correct AnswerverifiedShow Answer

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings.If the initial internal energy,U,is 61.2 kJ,what is the final value of U?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Chemical reactions in a bomb calorimeter occur at constant pressure.

Correct AnswerverifiedShow Answer

Which is not a state function?

Correct AnswerverifiedShow Answer

For which of the substances below is ΔHof = 0?

Correct AnswerverifiedShow Answer

What is ΔH°rxn for the following reaction? SiO2(s) + 4HCl(g) → SiCl4(g) + 2H2O(g) Substance ΔH°f(kJ/mol) SiO2(s) -859.3 SiCl4(g) -662.8 HCl(g) -92.3 H2O(g) -241.8

Correct AnswerverifiedShow Answer

If two solutions are mixed together in a container and the container "feels hot",then

Correct AnswerverifiedShow Answer

A glass containing 200.0 g of H2O at 20.0°C was placed in a refrigerator.The water loses 11.7 kJ as it cools to a constant temperature.What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Consider the following two representations of chemical reactions.Each sphere represents 1 mol of atoms. What is ΔHºrxn for the following reaction? CS(g) + O(g) → CO(g) + S(g)

Correct AnswerverifiedShow Answer

For which reaction is ΔH approximately (or exactly) equal to ΔU?

Correct AnswerverifiedShow Answer

An endothermic reaction causes the surroundings to

Correct AnswerverifiedShow Answer

The dissolution of barium hydroxide in water is an exothermic process.Which statement is correct?

Correct AnswerverifiedShow Answer

The combustion of pentane produces heat according to the following thermochemical equation. C5H12(l) + 8O2(g) → 5CO2(g) + 6H2O(l) ΔH°rxn = -3510 kJ/mol How many grams of CO2 is produced per 2.50 × 103 kJ of heat released?

Correct AnswerverifiedShow Answer

A system delivers 1275 J of heat while the surroundings perform 854 J of work on it.What is ΔU of the system?

Correct AnswerverifiedShow Answer

A student used a bomb calorimeter to determine the heat of combustion of an unknown compound.If the student ignored the heat capacity of the bomb calorimeter,the heat capacity of the unknown compound would be _________ the accepted value.

Correct AnswerverifiedShow Answer

How much heat is released if 7.15 g CaO(s) is added to 152 g of H2O(l) ? CaO(s) + H2O(l) → Ca(OH) 2(s) ΔH°rxn = -64.8 kJ/mol

Correct AnswerverifiedShow Answer

What is ΔH°rxn for the following reaction? NO2(g) + CO(g) → CO2(g) + NO(g) Substance ΔH°f(kJ/mol) NO(g) +90.4 NO2(g) +33.85 CO(g) -110.5 CO2(g) -393.5

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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For which of the substances below is ΔH^o_f = 0?

Correct Answer
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What is ΔH°_rxn for the following reaction? SiO₂(s) + 4HCl(g) → SiCl₄(g) + 2H₂O(g) Substance ΔH°_f(kJ/mol) SiO₂(s) -859.3 SiCl₄(g) -662.8 HCl(g) -92.3 H₂O(g) -241.8

Correct Answer
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Correct Answer
verified

A glass containing 200.0 g of H₂O at 20.0°C was placed in a refrigerator.The water loses 11.7 kJ as it cools to a constant temperature.What is its new temperature? The specific heat of water is 4.184 J/g·°C.

Correct Answer
verified

Correct Answer
verified

Consider the following two representations of chemical reactions.Each sphere represents 1 mol of atoms. What is ΔHº_rxn for the following reaction? CS(g) + O(g) → CO(g) + S(g)

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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The combustion of pentane produces heat according to the following thermochemical equation. C₅H₁₂(l) + 8O₂(g) → 5CO₂(g) + 6H₂O(l) ΔH°_rxn = -3510 kJ/mol How many grams of CO₂ is produced per 2.50 × 10³ kJ of heat released?

Correct Answer
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Correct Answer
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Correct Answer
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How much heat is released if 7.15 g CaO(s) is added to 152 g of H₂O(l) ? CaO(s) + H₂O(l) → Ca(OH) ₂(s) ΔH°_rxn = -64.8 kJ/mol

Correct Answer
verified

What is ΔH°_rxn for the following reaction? NO₂(g) + CO(g) → CO₂(g) + NO(g) Substance ΔH°_f(kJ/mol) NO(g) +90.4 NO₂(g) +33.85 CO(g) -110.5 CO₂(g) -393.5

Correct Answer
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