Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

An expansion of gas by a system means that the internal energy of the system increases.

Accepted Answer

A) True 
 B)False

Question 3

Two solutions,50.0 mL of 1.00 M BaCl2(aq)and 50.0 mL of 1.00 M Na2SO4(aq),both initially at 21.5 °C,are added to a calorimeter with a total heat capacity,after the solutions are added,of 1.10 kJ/ °C and the temperature rises to 22.7 °C.Determine qrxn per mole of BaSO4(s)formed in the reaction.

Accepted Answer

A) -26.4 kJ/mol 
B) +26.4 kJ/mol 
C) -2.64 kJ/mol 
D) +2.64 kJ/mol 
A) -26.4 kJ/mol 
B) +26.4 kJ/mol 
C) -2.64 kJ/mol 
D) +2.64 kJ/mol

Question 4

8.000 moles of H2(g)reacts with 4.000 mol of O2(g)to form 8.000 mol of H2O(l)at 25 °C and a constant pressure of 1.0133 bar.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then:

Accepted Answer

A) ΔH° = +546.4 kJ and ΔU = +576.06 kJ 
B) ΔH° = +546.4 kJ and ΔU = +516.8 kJ 
C) ΔH° = -546.4 kJ and ΔU = -516.8 kJ 
D) ΔH° = -546.4 kJ and ΔU = -576.0 kJ 
A) ΔH° = +546.4 kJ and ΔU = +576.06 kJ 
B) ΔH° = +546.4 kJ and ΔU = +516.8 kJ 
C) ΔH° = -546.4 kJ and ΔU = -516.8 kJ 
D) ΔH° = -546.4 kJ and ΔU = -576.0 kJ

Question 5

What is the enthalpy change (in kJ)of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g mL-1
By 10.2 °C? 
(The specific heat of the solution is 3.733 J g-1k-1. )

Accepted Answer

A) -7.43 kJ 
B) -12.51 kJ 
C) 8.20 kJ 
D) -11.9 kJ 
E) 6.51 kJ 
A) -7.43 kJ 
B) -12.51 kJ 
C) 8.20 kJ 
D) -11.9 kJ 
E) 6.51 kJ

Question 6

The specific heat capacity of solid copper metal is 0.385 J g-1k-1
.How many joules of heat are needed to raise the temperature of a 1.55 kg block of copper from 33.0 °C to 77.5 °C?

Accepted Answer

A) 1.79 ×   J 
B) 26.6 J 
C) 2.66 ×   J 
D) 5.58 ×   J 
E) 0.00558 J 
A) 1.79 ×   J 
B) 26.6 J 
C) 2.66 ×   J 
D) 5.58 ×   J 
E) 0.00558 J

Question 7

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

Question 8

Calculate the enthalpy change for the following reaction at 25 °C.The value of ΔfH° in kJ/mol is given below each species:

Accepted Answer

A) -49.6 kJ/mol 
B) 541 kJ/mol 
C) -1380 kJ/mol 
D) -3350 kJ/mol 
E) -24.8 kJ/mol 
A) -49.6 kJ/mol 
B) 541 kJ/mol 
C) -1380 kJ/mol 
D) -3350 kJ/mol 
E) -24.8 kJ/mol

Question 9

246 g of hot coffee at 86.0 °C are placed in a 137 g mug at 20.0 °C.The specific heat of coffee is 4.00 J/g °C,while that of the mug is 0.752 J/g °C.Assuming no heat is lost to the surroundings,what is the final temperature of the system: mug + coffee?

Accepted Answer

A) 79.7 °C 
B) 93.7 °C 
C) 98.4 °C 
D) 76.0 °C 
E) 53.0 °C 
A) 79.7 °C 
B) 93.7 °C 
C) 98.4 °C 
D) 76.0 °C 
E) 53.0 °C

Question 10

Two solutions,250.0 mL of 1.00 M CaCl2(aq)and 250.0 mL of 1.00 M K2SO4(aq),are added to a calorimeter with a total heat capacity,after the solutions are added,of 1.25 kJ/ °C and the temperature decreased by 2.40 °C.Determine qrxn per mole of CaSO4(s)formed in the reaction.

Accepted Answer

A) +12.0 kJ/mol 
B) -12.0 kJ/mol 
C) +6.00 kJ/mol 
D) -6.00 kJ/mol 
A) +12.0 kJ/mol 
B) -12.0 kJ/mol 
C) +6.00 kJ/mol 
D) -6.00 kJ/mol

Question 11

How much heat is absorbed when 45.00 g of C(s)reacts in the presence of excess SO2(g)to produce CS2(l)and CO(g)according to the following chemical equation?
5 C(s)+ 2 SO2(g)→ CS2(l)+ 4 CO(g)  
H° = 239.9 kJ

Accepted Answer

A) 179.8 kJ 
B) 239.9 kJ 
C) 898.5 kJ 
D) 2158 kJ 
A) 179.8 kJ 
B) 239.9 kJ 
C) 898.5 kJ 
D) 2158 kJ

Question 12

How much heat is involved in the complete combustion of 2.50 kg propane,C3H8?
ΔrHcomb = -2219 kJ/mol

Accepted Answer

A) 1.26 × 105 kJ 
B) 5.55 × 103 kJ 
C) 126 kJ 
D) 503 kJ 
E) 49.7 kJ 
A) 1.26 × 105 kJ 
B) 5.55 × 103 kJ 
C) 126 kJ 
D) 503 kJ 
E) 49.7 kJ

Question 13

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-(aq)→ 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-(aq)→ 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 14

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below.When 0.015 mol of Na is added to 100.00 g of water,the temperature of the resulting solution rises from 25.00 °C to 31.45 °C.If the specific heat of the solution is 4.18 J g-1°C-1 ,calculate ΔH for the reaction,as written.
2 Na(s)+ 2 H2O(l)→ 2 NaOH(aq)+ H2(g) 
  H = ?

Accepted Answer

A) -5.41 kJ 
B) -90.0 kJ 
C) -180 kJ 
D) -360 kJ 
A) -5.41 kJ 
B) -90.0 kJ 
C) -180 kJ 
D) -360 kJ

Question 15

How much work,in joules,is done when the pressure is suddenly released from 4.56 atm to 1.23 atm on 45.4 g of O2 at 44 °C?

Accepted Answer

A) 386 J 
B) -477 J 
C) -2.74 × 103 J 
D) 2.74 × 103 J 
E) 477 J 
A) 386 J 
B) -477 J 
C) -2.74 × 103 J 
D) 2.74 × 103 J 
E) 477 J

Question 16

5.04 × 10-3 mole of a compound is added to 41.0 g of water in a styrofoam cup and stirred until it dissolves.The temperature of the solution changes from 23.460 °C to 23.420 °C.What is the heat of solution of the compound expressed in kJ/mol? Assume the specific heat of the solution is 4.18 J/g °C.

Accepted Answer

A) -0.035 kJ/mol 
B) 1.4 kJ/mol 
C) -1.4 kJ/mol 
D) -2.8 kJ/mol 
E) 2.8 kJ/mol 
A) -0.035 kJ/mol 
B) 1.4 kJ/mol 
C) -1.4 kJ/mol 
D) -2.8 kJ/mol 
E) 2.8 kJ/mol

Question 17

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ΔH for the reaction given below?
2C2H6(g)+ 7O2(g)→ 4CO2(g)+ 6H2O(l)

Accepted Answer

A) -173 kJ mol-1 
B) -779 kJ mol-1 
C) -1560 kJ mol-1 
D) -3115 kJ mol-1 
A) -173 kJ mol-1 
B) -779 kJ mol-1 
C) -1560 kJ mol-1 
D) -3115 kJ mol-1

Question 18

How much heat is needed to raise the temperature of 5.28 gal of water from 25.0 °C to 88.0 °C(1 gal = 3.785 L)?

Accepted Answer

A) 5260 kJ 
B) 997 kJ 
C) 1390 kJ 
D) 316 kJ 
E) 133 kJ 
A) 5260 kJ 
B) 997 kJ 
C) 1390 kJ 
D) 316 kJ 
E) 133 kJ

Question 19

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

Accepted Answer

A) -1000.6 kJ/mol 
B) -500.3 kJ /mol 
C) 500.3 kJ /mol 
D) -2365.1 kJ /mol 
E) -1094.1 kJ/mol 
A) -1000.6 kJ/mol 
B) -500.3 kJ /mol 
C) 500.3 kJ /mol 
D) -2365.1 kJ /mol 
E) -1094.1 kJ/mol

Question 20

If 356 J of work is done by a system while it loses 289 J of heat,what is the value of

Accepted Answer

A) +645 J 
B) -645 J 
C) +67 J 
D) -67 J 
E) +134 J 
A) +645 J 
B) -645 J 
C) +67 J 
D) -67 J 
E) +134 J

Exam 7: Thermochemistry

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

An expansion of gas by a system means that the internal energy of the system increases.

Two solutions,50.0 mL of 1.00 M BaCl2(aq)and 50.0 mL of 1.00 M Na2SO4(aq),both initially at 21.5 °C,are added to a calorimeter with a total heat capacity,after the solutions are added,of 1.10 kJ/ °C and the temperature rises to 22.7 °C.Determine qrxn per mole of BaSO4(s)formed in the reaction.

8.000 moles of H2(g)reacts with 4.000 mol of O2(g)to form 8.000 mol of H2O(l)at 25 °C and a constant pressure of 1.0133 bar.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then:

What is the enthalpy change (in kJ)of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g mL-1 By 10.2 °C? (The specific heat of the solution is 3.733 J g-1k-1. )

The specific heat capacity of solid copper metal is 0.385 J g-1k-1 .How many joules of heat are needed to raise the temperature of a 1.55 kg block of copper from 33.0 °C to 77.5 °C?

An example of a fossil fuel is:

Calculate the enthalpy change for the following reaction at 25 °C.The value of ΔfH° in kJ/mol is given below each species:

246 g of hot coffee at 86.0 °C are placed in a 137 g mug at 20.0 °C.The specific heat of coffee is 4.00 J/g °C,while that of the mug is 0.752 J/g °C.Assuming no heat is lost to the surroundings,what is the final temperature of the system: mug + coffee?

Two solutions,250.0 mL of 1.00 M CaCl2(aq)and 250.0 mL of 1.00 M K2SO4(aq),are added to a calorimeter with a total heat capacity,after the solutions are added,of 1.25 kJ/ °C and the temperature decreased by 2.40 °C.Determine qrxn per mole of CaSO4(s)formed in the reaction.

How much heat is absorbed when 45.00 g of C(s)reacts in the presence of excess SO2(g)to produce CS2(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO2(g)→ CS2(l)+ 4 CO(g) H° = 239.9 kJ

How much heat is involved in the complete combustion of 2.50 kg propane,C3H8? ΔrHcomb = -2219 kJ/mol

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

How much work,in joules,is done when the pressure is suddenly released from 4.56 atm to 1.23 atm on 45.4 g of O2 at 44 °C?

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ΔH for the reaction given below? 2C2H6(g)+ 7O2(g)→ 4CO2(g)+ 6H2O(l)

How much heat is needed to raise the temperature of 5.28 gal of water from 25.0 °C to 88.0 °C(1 gal = 3.785 L)?

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

If 356 J of work is done by a system while it loses 289 J of heat,what is the value of

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

Filters

8.000 moles of H₂(g)reacts with 4.000 mol of O₂(g)to form 8.000 mol of H₂O(l)at 25 °C and a constant pressure of 1.0133 bar.If 546.4 kJ of heat are released during this reaction,and PΔV is equal to -29.60 kJ,then:

What is the enthalpy change (in kJ)of a chemical reaction that raises the temperature of 250.0 mL of solution having a density of 1.25 g mL^-1 By 10.2 °C? (The specific heat of the solution is 3.733 J g^-1k^-1. )

The specific heat capacity of solid copper metal is 0.385 J g^-1k^-1 .How many joules of heat are needed to raise the temperature of a 1.55 kg block of copper from 33.0 °C to 77.5 °C?

Calculate the enthalpy change for the following reaction at 25 °C.The value of Δ_fH° in kJ/mol is given below each species:

Two solutions,250.0 mL of 1.00 M CaCl₂(aq)and 250.0 mL of 1.00 M K₂SO₄(aq),are added to a calorimeter with a total heat capacity,after the solutions are added,of 1.25 kJ/ °C and the temperature decreased by 2.40 °C.Determine q_rxn per mole of CaSO₄(s)formed in the reaction.

How much heat is absorbed when 45.00 g of C(s)reacts in the presence of excess SO₂(g)to produce CS₂(l)and CO(g)according to the following chemical equation? 5 C(s)+ 2 SO₂(g)→ CS₂(l)+ 4 CO(g) H° = 239.9 kJ

How much heat is involved in the complete combustion of 2.50 kg propane,C₃H₈? Δ_rH_comb = -2219 kJ/mol

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

How much work,in joules,is done when the pressure is suddenly released from 4.56 atm to 1.23 atm on 45.4 g of O₂ at 44 °C?

At constant pressure,the combustion of 20.0 g of C₂H₆(g)releases 1036 kJ of heat.What is ΔH for the reaction given below? 2C₂H₆(g)+ 7O₂(g)→ 4CO₂(g)+ 6H₂O(l)

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