Question 1

What is the work in joules done on the system to compress He gas from 24.0 L to 12.5 L against a pressure of 1.5 atm at a constant temperature of 37.4°C?

Accepted Answer

A)  5.5 × 103 J 
B)  -17 J 
C)  17 J 
D)  1.7 × 103 J 
E)  -1.7 × 103 J 
A)  5.5 × 103 J 
B)  -17 J 
C)  17 J 
D)  1.7 × 103 J 
E)  -1.7 × 103 J D

Question 2

Choose the INCORRECT statement.

Accepted Answer

A)  Temperatures of two bodies are equal when the average kinetic energies of the two bodies become the same. 
B)  The heat capacity is the quantity of heat required to change the temperature of the system by one degree. 
C)  The specific heat is the heat capacity for one mole of substance. 
D)  The law of conservation of energy can be written: qsystem + qsurroundings = 0. 
E)  Most metals have low specific heats, as metals can be heated quickly. 
A)  Temperatures of two bodies are equal when the average kinetic energies of the two bodies become the same. 
B)  The heat capacity is the quantity of heat required to change the temperature of the system by one degree. 
C)  The specific heat is the heat capacity for one mole of substance. 
D)  The law of conservation of energy can be written: qsystem + qsurroundings = 0. 
E)  Most metals have low specific heats, as metals can be heated quickly. C

Question 3

Choose the INCORRECT statement.

Accepted Answer

A)  Kinetic energy is the energy of motion. 
B)  Potential energy is energy in action. 
C)  Heat is energy transferred as a result of a temperature difference. 
D)  Pressure volume work is calculated by w = P ∙ V. 
E)  Heat moves from a warmer body to a colder one. 
A)  Kinetic energy is the energy of motion. 
B)  Potential energy is energy in action. 
C)  Heat is energy transferred as a result of a temperature difference. 
D)  Pressure volume work is calculated by w = P ∙ V. 
E)  Heat moves from a warmer body to a colder one. B

Question 4

What is the reaction for the standard enthalpy of formation for CdSO4(s)? (Cd(s) is the stable form of cadmium.)

Accepted Answer

A)  Cd(NO3)2(aq) + H2SO4(aq) → 2 HNO3(aq) + CdSO4(s) 
B)  Cd2+ (aq) + 2 SO42- → CdSO4(s) 
C)  Cd(s) + 1/8 S8 (s) + 2O2(g) → CdSO4(s) 
D)  CdO(s) + SO3(l) → CdSO4(s) 
E)  Cd(s) + 1/8 S8 (s) + 4O(g) → CdSO4(s) 
A)  Cd(NO3)2(aq) + H2SO4(aq) → 2 HNO3(aq) + CdSO4(s) 
B)  Cd2+ (aq) + 2 SO42- → CdSO4(s) 
C)  Cd(s) + 1/8 S8 (s) + 2O2(g) → CdSO4(s) 
D)  CdO(s) + SO3(l) → CdSO4(s) 
E)  Cd(s) + 1/8 S8 (s) + 4O(g) → CdSO4(s)

Question 5

Given the reactions below, compute ΔH° for the reaction: (ΔH's are all given in kJ)
2 MnO2(s) + CO(g) → Mn2O3(s) + CO2(g)
Reaction ΔH°rxn
MnO2(s) + CO(g) → MnO(s) + CO2(g)   &emsp;- 150.6
Mn3O4(s) + CO(g) → 3 MnO(s) + CO2(g)  &emsp; - 54.4
3 Mn2O3(s) + CO(g) → 2 Mn3O4(s) + CO2(g)  &emsp; - 142.3

Accepted Answer

A)  -347.3 kJ 
B)  -46.1 kJ 
C)  -217.1 kJ 
D)  -104.5 kJ 
E)  -389.1 kJ 
A)  -347.3 kJ 
B)  -46.1 kJ 
C)  -217.1 kJ 
D)  -104.5 kJ 
E)  -389.1 kJ

Question 6

Given that ΔH°f [CO(g)] = -110.5 kJ/mol and ΔH°f [COCl2(g)] = -219.1 kJ/mol, what is the enthalpy of reaction for the formation of phosgene, COCl2 from carbon monoxide, CO, and chlorine gas, Cl2(g)?

Accepted Answer

A)  +110.5 kJ 
B)  -110.5 kJ 
C)  +329.6 kJ 
D)  -108.6 kJ 
E)  -219.1 kJ 
A)  +110.5 kJ 
B)  -110.5 kJ 
C)  +329.6 kJ 
D)  -108.6 kJ 
E)  -219.1 kJ

Question 7

A system absorbs 623 J of heat while doing 457 J of work. What is the value of ΔU?

Accepted Answer

A)  +1080 J 
B)  -166 J 
C)  +166 J 
D)  -1080 J 
E)  +623 J 
A)  +1080 J 
B)  -166 J 
C)  +166 J 
D)  -1080 J 
E)  +623 J

Question 8

Combine the reactions: P4(s) + 6 Cl2(g) → 4 PCl3(g) ΔH°298 = -1225.0 kJ
PCl3(g) + 3 H2O(l) → H3PO3(aq) + 3 HCl(aq) = - 853.5 kJ
2 H2(g) + O2(g) → 2 H2O(l) = - 571.5 kJ
H2(g) + Cl2(g) → 2 HCl(g) = - 184.9 kJ
To obtain the reaction: P4(s) + 6 H2(g) + 6 O2(g) → 4 H3PO3(aq).
What is the value of ΔH°298 for this reaction?

Accepted Answer

A)  -2465.1 kJ 
B)  -6958.6 kJ 
C)  -2834.9 kJ 
D)  -9177.4 kJ 
E)  8605.9 kJ 
A)  -2465.1 kJ 
B)  -6958.6 kJ 
C)  -2834.9 kJ 
D)  -9177.4 kJ 
E)  8605.9 kJ

Question 9

The heat of combustion, ΔHcomb, of 1-butene(l), C4H8(l), is -2696.9 kJ/mole. From the following values of ΔH°f CO2(g) = -393.5 kJ/mol and ΔH°f H2O(l) = -285.8 kJ/mol, calculate the standard enthalpy of formation of butene(l).

Accepted Answer

A)  +2017 kJ 
B)  -2017 kJ 
C)  -3376 kJ 
D)  -107.7 kJ 
E)  -20.30 kJ 
A)  +2017 kJ 
B)  -2017 kJ 
C)  -3376 kJ 
D)  -107.7 kJ 
E)  -20.30 kJ

Question 10

2 NOCl(g) → 2 NO(g) + Cl2(g)   &emsp;ΔH° = +75.56 kJ
 2 NO(g) + O2(g) → 2 NO2(g)   &emsp;ΔH° = -113.05 kJ
2 NO2(g) → N2O4(g)  &emsp; ΔH° = -58.03 kJ
Compute ΔH° of N2O4(g) + Cl2(g) → 2 NOCl(g) + O2(g) in kJ.

Accepted Answer

A)  +246.65 
B)  -95.52 
C)  -246.65 
D)  +95.52 
E)  none of these 
A)  +246.65 
B)  -95.52 
C)  -246.65 
D)  +95.52 
E)  none of these

Question 11

Determine △H° for the decomposition of hydrogen peroxide. H2O2(l) →   O2(g) + H2O(l)
Given: H2(g) + O2(g) → H2O2(l) △H° = -187.78 kJ
H2(g) +   O2(g) → H2O(l) △H° = -285.83 kJ

Accepted Answer

A)  -98.05 kJ 
B)  +93.89 kJ 
C)  -191.94 kJ 
D)  -93.89 kJ 
A)  -98.05 kJ 
B)  +93.89 kJ 
C)  -191.94 kJ 
D)  -93.89 kJ

Question 12

1674 J of heat are absorbed by 25.0 mL of NaOH (d = 1.10 g/mL, specific heat = 4.10 J/g °C). The temperature of the NaOH goes up how many degrees?

Accepted Answer

A)  14.8 °C 
B)  18.0 °C 
C)  17.2 °C 
D)  14.2 °C 
E)  19.1 °C 
A)  14.8 °C 
B)  18.0 °C 
C)  17.2 °C 
D)  14.2 °C 
E)  19.1 °C

Question 13

Oxygen gas at 34.5°C expands from 34.5 L to 45.7 L against a constant pressure of 750 mmHg. What is the work done in joules by the system?

Accepted Answer

A)  1.12 × 103 J 
B)  -1.12 × 103 J 
C)  9.09 × 104 J 
D)  -9.09 × 104 J 
E)  4.55 × 103 J 
A)  1.12 × 103 J 
B)  -1.12 × 103 J 
C)  9.09 × 104 J 
D)  -9.09 × 104 J 
E)  4.55 × 103 J

Question 14

Which of the following has a standard enthalpy of formation of zero?

Accepted Answer

A)  Ar(g) 
B)  I2(g) 
C)  Br2(g) 
D)  O3(g) 
E)  P(s, red) 
A)  Ar(g) 
B)  I2(g) 
C)  Br2(g) 
D)  O3(g) 
E)  P(s, red)

Question 15

When power was turned off to a 30.0 gal. water heater, the temperature of the water dropped from 75.0°C to 22.5°C. How much heat was lost to the surroundings?

Accepted Answer

A)  -2.49 × 103 kJ 
B)  -2.49 × 107 kJ 
C)  -2.49 × 104 kJ 
D)  -2.49 × 1010 kJ 
E)  -2.49 kJ 
A)  -2.49 × 103 kJ 
B)  -2.49 × 107 kJ 
C)  -2.49 × 104 kJ 
D)  -2.49 × 1010 kJ 
E)  -2.49 kJ

Question 16

For the reaction H2(g) + 1/2 O2(g) → H2O(g) ΔH° = -241.8 kJ/mol, what quantity of heat is liberated by the reaction of 10.0 L of O2 measured at 22.0°C and 742 mmHg?

Accepted Answer

A)  120 kJ 
B)  2610 kJ 
C)  1310 kJ 
D)  195 kJ 
E)  97.5 kJ 
A)  120 kJ 
B)  2610 kJ 
C)  1310 kJ 
D)  195 kJ 
E)  97.5 kJ

Question 17

Although CO is not toxic, there is concern that it causes global warming.

Accepted Answer

A) True 
 B)False

Question 18

A sample gives off 2505 cal when burned in a bomb calorimeter. The calorimeter assembly increases by 2.24°C. What is the heat capacity of the calorimeter?

Accepted Answer

A)  8.92 kcal/°C 
B)  1.12 kcal/°C 
C)  2.51 kcal/°C 
D)  5.61 kcal/°C 
E)  2.65 kcal/°C 
A)  8.92 kcal/°C 
B)  1.12 kcal/°C 
C)  2.51 kcal/°C 
D)  5.61 kcal/°C 
E)  2.65 kcal/°C

Question 19

An expansion of gas by a system means that the system does work.

Accepted Answer

A) True 
 B)False

Question 20

An example of a fossil fuel is:

Accepted Answer

A)  the sun 
B)  chlorophyll 
C)  water 
D)  natural gas 
E)  carbon dioxide 
A)  the sun 
B)  chlorophyll 
C)  water 
D)  natural gas 
E)  carbon dioxide

Exam 7: Thermochemistry

What is the work in joules done on the system to compress He gas from 24.0 L to 12.5 L against a pressure of 1.5 atm at a constant temperature of 37.4°C?

Choose the INCORRECT statement.

Choose the INCORRECT statement.

What is the reaction for the standard enthalpy of formation for CdSO4(s)? (Cd(s) is the stable form of cadmium.)

Given the reactions below, compute ΔH° for the reaction: (ΔH's are all given in kJ) 2 MnO2(s) + CO(g) → Mn2O3(s) + CO2(g) Reaction ΔH°rxn MnO2(s) + CO(g) → MnO(s) + CO2(g) - 150.6 Mn3O4(s) + CO(g) → 3 MnO(s) + CO2(g) - 54.4 3 Mn2O3(s) + CO(g) → 2 Mn3O4(s) + CO2(g) - 142.3

Given that ΔH°f [CO(g)] = -110.5 kJ/mol and ΔH°f [COCl2(g)] = -219.1 kJ/mol, what is the enthalpy of reaction for the formation of phosgene, COCl2 from carbon monoxide, CO, and chlorine gas, Cl2(g)?

A system absorbs 623 J of heat while doing 457 J of work. What is the value of ΔU?

The heat of combustion, ΔHcomb, of 1-butene(l), C4H8(l), is -2696.9 kJ/mole. From the following values of ΔH°f CO2(g) = -393.5 kJ/mol and ΔH°f H2O(l) = -285.8 kJ/mol, calculate the standard enthalpy of formation of butene(l).

2 NOCl(g) → 2 NO(g) + Cl2(g) ΔH° = +75.56 kJ 2 NO(g) + O2(g) → 2 NO2(g) ΔH° = -113.05 kJ 2 NO2(g) → N2O4(g) ΔH° = -58.03 kJ Compute ΔH° of N2O4(g) + Cl2(g) → 2 NOCl(g) + O2(g) in kJ.

Determine △H° for the decomposition of hydrogen peroxide. H2O2(l) → O2(g) + H2O(l) Given: H2(g) + O2(g) → H2O2(l) △H° = -187.78 kJ H2(g) + O2(g) → H2O(l) △H° = -285.83 kJ

1674 J of heat are absorbed by 25.0 mL of NaOH (d = 1.10 g/mL, specific heat = 4.10 J/g °C). The temperature of the NaOH goes up how many degrees?

Oxygen gas at 34.5°C expands from 34.5 L to 45.7 L against a constant pressure of 750 mmHg. What is the work done in joules by the system?

Which of the following has a standard enthalpy of formation of zero?

When power was turned off to a 30.0 gal. water heater, the temperature of the water dropped from 75.0°C to 22.5°C. How much heat was lost to the surroundings?

For the reaction H2(g) + 1/2 O2(g) → H2O(g) ΔH° = -241.8 kJ/mol, what quantity of heat is liberated by the reaction of 10.0 L of O2 measured at 22.0°C and 742 mmHg?

Although CO is not toxic, there is concern that it causes global warming.

A sample gives off 2505 cal when burned in a bomb calorimeter. The calorimeter assembly increases by 2.24°C. What is the heat capacity of the calorimeter?

An expansion of gas by a system means that the system does work.

An example of a fossil fuel is:

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Chemical Reactions

Introduction to Reactions in Aqueous Solutions

Gases

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

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What is the reaction for the standard enthalpy of formation for CdSO₄(s)? (Cd(s) is the stable form of cadmium.)

Given that ΔH°f [CO(g)] = -110.5 kJ/mol and ΔH°f [COCl₂(g)] = -219.1 kJ/mol, what is the enthalpy of reaction for the formation of phosgene, COCl₂ from carbon monoxide, CO, and chlorine gas, Cl₂(g)?

The heat of combustion, ΔHcomb, of 1-butene(l), C₄H₈(l), is -2696.9 kJ/mole. From the following values of ΔH°f CO₂(g) = -393.5 kJ/mol and ΔH°f H₂O(l) = -285.8 kJ/mol, calculate the standard enthalpy of formation of butene(l).

2 NOCl(g) → 2 NO(g) + Cl₂(g) ΔH° = +75.56 kJ 2 NO(g) + O₂(g) → 2 NO₂(g) ΔH° = -113.05 kJ 2 NO₂(g) → N₂O₄(g) ΔH° = -58.03 kJ Compute ΔH° of N₂O₄(g) + Cl₂(g) → 2 NOCl(g) + O₂(g) in kJ.

Determine △H° for the decomposition of hydrogen peroxide. H₂O₂(l) → O₂(g) + H₂O(l) Given: H₂(g) + O₂(g) → H₂O₂(l) △H° = -187.78 kJ H₂(g) + O₂(g) → H₂O(l) △H° = -285.83 kJ

For the reaction H₂(g) + 1/2 O₂(g) → H₂O(g) ΔH° = -241.8 kJ/mol, what quantity of heat is liberated by the reaction of 10.0 L of O₂ measured at 22.0°C and 742 mmHg?