Question 1

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 40 L against a constant external pressure of 1.5199 bar.

Accepted Answer

A) -6.1 kJ 
B) -3.8 kJ 
C) +3.8 kJ 
D) +6.1 kJ 
A) -6.1 kJ 
B) -3.8 kJ 
C) +3.8 kJ 
D) +6.1 kJ

Question 2

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 3

Coal contains an impurity that reacts with oxygen during the combustion process,producing oxides that are major environmental pollutants.This impurity is:

Accepted Answer

A) acid rain 
B) nitrogen 
C) sulfur 
D) carbon dioxide 
E) peat 
A) acid rain 
B) nitrogen 
C) sulfur 
D) carbon dioxide 
E) peat

Question 4

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 = −PΔV. 
E) Heat is transferred 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 = −PΔV. 
E) Heat is transferred from a warmer body to a colder one.

Question 5

Compute ΔrH° for the following reaction.The value of ΔfH° in kJ/mol is given below each species:

Accepted Answer

A) -688.6 kJ/mol 
B) -200.1 kJ/mol 
C) -74.9 kJ/mol 
D) -1000.6 kJ/mol 
E) -900.3 kJ/mol 
A) -688.6 kJ/mol 
B) -200.1 kJ/mol 
C) -74.9 kJ/mol 
D) -1000.6 kJ/mol 
E) -900.3 kJ/mol

Question 6

For the reaction H2(g)+ 1/2 O2(g)→ H2O(g)ΔrH° = -241.8 kJ/mol,
What mass of H2(g)is required to liberate 1.00 × 103 kJ of heat?

Accepted Answer

A) 66.2 g 
B) 4.17 g 
C) 8.34 g 
D) 2.05 g 
E) 16.7 g 
A) 66.2 g 
B) 4.17 g 
C) 8.34 g 
D) 2.05 g 
E) 16.7 g

Question 7

The specific heat capacity of liquid mercury is 0.14 J g-1k-1.How many joules of heat are needed to raise the temperature of 5.00 g of mercury from 15.0 °C to 36.5 °C?

Accepted Answer

A) 7.7 × 102 J 
B) 15 J 
C) 36 J 
D) 0.0013 J 
E) 1.7 J 
A) 7.7 × 102 J 
B) 15 J 
C) 36 J 
D) 0.0013 J 
E) 1.7 J

Question 8

The complete combustion of propane,C3H8(g),is represented by the equation:
C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(l)ΔrH° = -2220 kJ /mol
How much heat is evolved in the complete combustion of 12.5 L C3H8(g)at 25 °C and 790 mmHg?

Accepted Answer

A) 8.27 × 104 kJ 
B) 1.41 × 104 kJ 
C) 653 kJ 
D) 168 kJ 
E) 1180 kJ 
A) 8.27 × 104 kJ 
B) 1.41 × 104 kJ 
C) 653 kJ 
D) 168 kJ 
E) 1180 kJ

Question 9

The standard enthalpy of formation of NH4Cl(s)is -315.4 kJ/mol.The equation that describes this △fH° is:

Accepted Answer

A) NH4+(aq)+ Cl-(aq)→ NH4Cl(s) 
B) 1/2 N2(g)+ 2 H2(g)+ 1/2 Cl2(g)→ NH4Cl(s) 
C) N2(g)+ H2(g)+ Cl2(g)→ 2 NH4Cl(s) 
D) 1/2 N2(g)+ 1/2 Cl2(g)+ 1/2 H2(g)→ NH4Cl(s) 
E) N2(g)+ Cl2(g)+ 4 H2(g)→ 2 NH4Cl(s) 
A) NH4+(aq)+ Cl-(aq)→ NH4Cl(s) 
B) 1/2 N2(g)+ 2 H2(g)+ 1/2 Cl2(g)→ NH4Cl(s) 
C) N2(g)+ H2(g)+ Cl2(g)→ 2 NH4Cl(s) 
D) 1/2 N2(g)+ 1/2 Cl2(g)+ 1/2 H2(g)→ NH4Cl(s) 
E) N2(g)+ Cl2(g)+ 4 H2(g)→ 2 NH4Cl(s)

Question 10

Kinetic energy is the energy of motion.

Accepted Answer

A) True 
 B)False

Question 11

Given the heat of formation of the following compounds:
 
What is the value of ΔrH° for the reaction:
CH3OH(l)+ 3/2 O2(g)→ CO2(g)+ 2 H2O(l)

Accepted Answer

A) -440.8 kJ/mol 
B) -416.9 kJ/mol 
C) -1203.9 kJ/mol 
D) -346.2 kJ/mol 
E) -726.7 kJ/mol 
A) -440.8 kJ/mol 
B) -416.9 kJ/mol 
C) -1203.9 kJ/mol 
D) -346.2 kJ/mol 
E) -726.7 kJ/mol

Question 12

To have a standard enthalpy of formation referenced to 0 J/mol,the substance must:
I.be a simple substance (chemical element)
II.be in its most stable form
III.be under 1 bar of pressure
IV.have a concentration of 1.0000 M

Accepted Answer

A) I,III,IV 
B) I,II,III 
C) II,IV 
D) I,III 
E) II,III,IV 
A) I,III,IV 
B) I,II,III 
C) II,IV 
D) I,III 
E) II,III,IV

Question 13

Calculate ΔU for a system that loses 475 kJ of heat and does 155 kJ of expansion work on the surroundings.

Accepted Answer

A) -630 kJ 
B) -320 kJ 
C) +630 kJ 
D) +320 kJ 
A) -630 kJ 
B) -320 kJ 
C) +630 kJ 
D) +320 kJ

Question 14

Determine the enthalpy change in the following equation:
Cl2(g)+ H2O(l)→ 2 HCl(g)+ 1/2 O2(g)
ΔfH° H2O(l)= -285.8 kJ/mol
ΔfH° HCl(g)= -92.31 kJ/mol

Accepted Answer

A) 193.5 kJ/mol 
B) -470.4 kJ/mol 
C) 470.4 kJ/mol 
D) 101.2 kJ/mol 
E) -101.2 kJ/mol 
A) 193.5 kJ/mol 
B) -470.4 kJ/mol 
C) 470.4 kJ/mol 
D) 101.2 kJ/mol 
E) -101.2 kJ/mol

Question 15

Consider the reaction: 
 
Compute ΔrH° for this reaction.

Accepted Answer

A) -994.67 kJ/mol 
B) 23.05 kJ /mol 
C) -23.05 kJ /mol 
D) 69.25 kJ /mol 
E) -69.25 kJ/mol 
A) -994.67 kJ/mol 
B) 23.05 kJ /mol 
C) -23.05 kJ /mol 
D) 69.25 kJ /mol 
E) -69.25 kJ/mol

Question 16

Calculate ΔfH° of octane,C8H18(l),given the enthalpy of combustion of octane to CO2(g)and H2O(l),-5471 kJ/mol,and the standard enthalpies of formation of CO2(g)and H2O(l),-393.5 kJ/mol and -285.8 kJ/mol,respectively.

Accepted Answer

A) -249.2 kJ/mol 
B) +4792 kJ/mol 
C) +249.2 kJ/mol 
D) -4792 kJ/mol 
A) -249.2 kJ/mol 
B) +4792 kJ/mol 
C) +249.2 kJ/mol 
D) -4792 kJ/mol

Question 17

From the following thermochemical equations,calculate ΔrH° for the reaction:
SO2(g)+ NO2(g)→ SO3(g)+ NO(g)
2 SO2(g)+ O2(g)→ 2 SO3(g)ΔrH° = -197.8 kJ/mol
2 NO(g)+ O2(g)→ 2 NO2(g)ΔrH° = -114.14 kJ/mol

Accepted Answer

A) -83.66 kJ /mol 
B) -311.9 kJ/mol 
C) +155.9 kJ/mol 
D) -155.9 kJ/mol 
E) -41.83 kJ/mol 
A) -83.66 kJ /mol 
B) -311.9 kJ/mol 
C) +155.9 kJ/mol 
D) -155.9 kJ/mol 
E) -41.83 kJ/mol

Question 18

The standard enthalpy for diamond and graphite are the same value.

Accepted Answer

A) True 
 B)False

Question 19

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy.The final temperature of the copper is ________ °C.The specific heat capacity of copper is

Accepted Answer

A) 32.3 
B) 25.0 
C) 25.5 
D) 75.5 
E) 50.5 
A) 32.3 
B) 25.0 
C) 25.5 
D) 75.5 
E) 50.5

Question 20

A closed system can exchange matter but not energy with the surroundings.

Accepted Answer

A) True 
 B)False

Exam 7: Thermochemistry

Calculate the work,w,gained or lost by the system when a gas expands from 15 L to 40 L against a constant external pressure of 1.5199 bar.

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?

Coal contains an impurity that reacts with oxygen during the combustion process,producing oxides that are major environmental pollutants.This impurity is:

Choose the INCORRECT statement.

Compute ΔrH° for the following reaction.The value of ΔfH° in kJ/mol is given below each species:

For the reaction H2(g)+ 1/2 O2(g)→ H2O(g)ΔrH° = -241.8 kJ/mol, What mass of H2(g)is required to liberate 1.00 × 103 kJ of heat?

The specific heat capacity of liquid mercury is 0.14 J g-1k-1.How many joules of heat are needed to raise the temperature of 5.00 g of mercury from 15.0 °C to 36.5 °C?

The complete combustion of propane,C3H8(g),is represented by the equation: C3H8(g)+ 5 O2(g)→ 3 CO2(g)+ 4 H2O(l)ΔrH° = -2220 kJ /mol How much heat is evolved in the complete combustion of 12.5 L C3H8(g)at 25 °C and 790 mmHg?

The standard enthalpy of formation of NH4Cl(s)is -315.4 kJ/mol.The equation that describes this △fH° is:

Kinetic energy is the energy of motion.

Given the heat of formation of the following compounds: What is the value of ΔrH° for the reaction: CH3OH(l)+ 3/2 O2(g)→ CO2(g)+ 2 H2O(l)

To have a standard enthalpy of formation referenced to 0 J/mol,the substance must: I.be a simple substance (chemical element) II.be in its most stable form III.be under 1 bar of pressure IV.have a concentration of 1.0000 M

Calculate ΔU for a system that loses 475 kJ of heat and does 155 kJ of expansion work on the surroundings.

Determine the enthalpy change in the following equation: Cl2(g)+ H2O(l)→ 2 HCl(g)+ 1/2 O2(g) ΔfH° H2O(l)= -285.8 kJ/mol ΔfH° HCl(g)= -92.31 kJ/mol

Consider the reaction: Compute ΔrH° for this reaction.

Calculate ΔfH° of octane,C8H18(l),given the enthalpy of combustion of octane to CO2(g)and H2O(l),-5471 kJ/mol,and the standard enthalpies of formation of CO2(g)and H2O(l),-393.5 kJ/mol and -285.8 kJ/mol,respectively.

From the following thermochemical equations,calculate ΔrH° for the reaction: SO2(g)+ NO2(g)→ SO3(g)+ NO(g) 2 SO2(g)+ O2(g)→ 2 SO3(g)ΔrH° = -197.8 kJ/mol 2 NO(g)+ O2(g)→ 2 NO2(g)ΔrH° = -114.14 kJ/mol

The standard enthalpy for diamond and graphite are the same value.

A 5.00 g sample of copper metal at 25.0 °C is heated by the addition of 96.0 J of energy.The final temperature of the copper is ________ °C.The specific heat capacity of copper is

A closed system can exchange matter but not energy with the surroundings.

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: Valence Bond and Molecular Orbital Theories

Intermolecular Forces: Liquids and Solids

Spontaneous Change: Entropy and Gibbs Energy

Solutions and Their Physical Properties

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acidbase Equilibria

Solubility and Complex-Ion Equilibria

Electrochemistry

Chemical Kinetics

Chemistry of the Main-Group Elements I: Groups 1,2,13,and 14

Chemistry of the Main-Group Elements Ii: Groups 18,17,16,15,and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

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Compute Δ_rH° for the following reaction.The value of Δ_fH° in kJ/mol is given below each species:

For the reaction H₂(g)+ 1/2 O₂(g)→ H₂O(g)Δ_rH° = -241.8 kJ/mol, What mass of H₂(g)is required to liberate 1.00 × 10³ kJ of heat?

The specific heat capacity of liquid mercury is 0.14 J g^-1k^-1.How many joules of heat are needed to raise the temperature of 5.00 g of mercury from 15.0 °C to 36.5 °C?

The complete combustion of propane,C₃H₈(g),is represented by the equation: C₃H₈(g)+ 5 O₂(g)→ 3 CO₂(g)+ 4 H₂O(l)Δ_rH° = -2220 kJ /mol How much heat is evolved in the complete combustion of 12.5 L C₃H₈(g)at 25 °C and 790 mmHg?

The standard enthalpy of formation of NH₄Cl(s)is -315.4 kJ/mol.The equation that describes this △_fH° is:

Given the heat of formation of the following compounds: What is the value of Δ_rH° for the reaction: CH₃OH(l)+ 3/2 O₂(g)→ CO₂(g)+ 2 H₂O(l)

Determine the enthalpy change in the following equation: Cl₂(g)+ H₂O(l)→ 2 HCl(g)+ 1/2 O₂(g) Δ_fH° H₂O(l)= -285.8 kJ/mol Δ_fH° HCl(g)= -92.31 kJ/mol

Consider the reaction: Compute Δ_rH° for this reaction.

Calculate Δ_fH° of octane,C₈H₁₈(l),given the enthalpy of combustion of octane to CO₂(g)and H₂O(l),-5471 kJ/mol,and the standard enthalpies of formation of CO₂(g)and H₂O(l),-393.5 kJ/mol and -285.8 kJ/mol,respectively.

From the following thermochemical equations,calculate Δ_rH° for the reaction: SO₂(g)+ NO₂(g)→ SO₃(g)+ NO(g) 2 SO₂(g)+ O₂(g)→ 2 SO₃(g)Δ_rH° = -197.8 kJ/mol 2 NO(g)+ O₂(g)→ 2 NO₂(g)Δ_rH° = -114.14 kJ/mol