Question 1

The value of ΔH° for the following reaction is -3351 kJ: 2Al (s)+ 3O2 (g)→ 2 Al2O3 (s)
The value of ΔHf ° for Al2O3 (s)is __________ kJ.

Accepted Answer

A) -3351 
B) -1676 
C) -32.86 
D) -16.43 
E) +3351 
A) -3351 
B) -1676 
C) -32.86 
D) -16.43 
E) +3351

Question 2

The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ)released to the surroundings when 38.5 g of O2 (g)reacts with excess CO. 2CO (g)+ O2 (g)→ 2CO2 (g)

Accepted Answer

A) 2.65 ×   
B) 482 
C) 580. 
D) 65.7 
E) 210. 
A) 2.65 ×   
B) 482 
C) 580. 
D) 65.7 
E) 210.

Question 3

Given the data in the table below, ΔH°rxn for the reaction C2H5OH (l)+ O2 (g)→ CH3CO2H (l)+ H2O (l)
Is __________ kJ.

Accepted Answer

A) -79.0 
B) -1048.0 
C) -476.4 
D) -492.6 
E) The value of ΔHf° of O2 (g)is required for the calculation. 
A) -79.0 
B) -1048.0 
C) -476.4 
D) -492.6 
E) The value of ΔHf° of O2 (g)is required for the calculation.

Question 4

The value of ΔH° for the reaction below is -186 kJ. H2 (g)+ Cl2 (g)→ 2HCl (g)
The value of ΔHf° for HCl (g)is __________ kJ/mol.

Accepted Answer

A) -3.72 ×   
B) -1.27 ×   
C) -93.0 
D) -186 
E) +186 
A) -3.72 ×   
B) -1.27 ×   
C) -93.0 
D) -186 
E) +186

Question 5

The primary component of natural gas is propane.

Accepted Answer

A) True 
 B)False

Question 6

ΔH for an endothermic process is __________ while ΔH for an exothermic process is __________.

Accepted Answer

A) zero, positive 
B) zero, negative 
C) positive, zero 
D) negative, positive 
E) positive, negative 
A) zero, positive 
B) zero, negative 
C) positive, zero 
D) negative, positive 
E) positive, negative

Question 7

For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for the product?

Accepted Answer

A) H2 (g)+ 1/2 O2 (g)→ H2O (l) 
B) H2 (g)+ O2 (g)→ H2O2 (l) 
C) 2 C (s, graphite)+ 2 H2 (g)→ C2H4 (g) 
D) 1/2 N2 (g)+ O2 (g)→ NO2 (g) 
E) all of the above 
A) H2 (g)+ 1/2 O2 (g)→ H2O (l) 
B) H2 (g)+ O2 (g)→ H2O2 (l) 
C) 2 C (s, graphite)+ 2 H2 (g)→ C2H4 (g) 
D) 1/2 N2 (g)+ O2 (g)→ NO2 (g) 
E) all of the above

Question 8

For the species in the reaction below, ΔHf° is zero for __________. 2Co (s)+ H2 (g)+ 8PF3 (g)→ 2HCo(PF3)4 (l)

Accepted Answer

A) Co (s) 
B) H2 (g) 
C) PF3 (g) 
D) HCo(PF3)4 (l) 
E) both Co(s)and H2 (g) 
A) Co (s) 
B) H2 (g) 
C) PF3 (g) 
D) HCo(PF3)4 (l) 
E) both Co(s)and H2 (g)

Question 9

The kinetic energy of a 10.3 g golf ball traveling at 48.0 m/s is __________ J.

Accepted Answer

A) 1.20 × 103 
B) 66 
C) 11.9 
D) 1.3 × 102 
E) 23.7 
A) 1.20 × 103 
B) 66 
C) 11.9 
D) 1.3 × 102 
E) 23.7

Question 10

Given the data in the table below, ΔH°rxn for the reaction IF5 (g)+ F2 (g)→ IF7 (g)
Is __________ kJ.

Accepted Answer

A) 1801 
B) -1801 
C) 121 
D) -121 
E) -101 
A) 1801 
B) -1801 
C) 121 
D) -121 
E) -101

Question 11

Given the following reactions H2O (l)→ H2O (g)ΔH = 44.01 kJ
2 H2 (g)+ O2 (g)→ 2 H2O (g)ΔH = -483.64 kJ
The enthalpy for the decomposition of liquid water into gaseous hydrogen and oxygen
2 H2O (l)→ 2 H2 (g)+ O2 (g)
Is __________ kJ.

Accepted Answer

A) -395.62 
B) -527.65 
C) 439.63 
D) 571.66 
E) 527.65 
A) -395.62 
B) -527.65 
C) 439.63 
D) 571.66 
E) 527.65

Question 12

Given the following reactions N2 (g)+ O2 (g)→ 2NO (g)ΔH = +180.7 kJ
2NO (g)+ O2 (g)→ 2N O2 (g)ΔH = -113.1 kJ
The enthalpy of reaction for
4NO (g)→ 2NO2 (g)+ N2 (g)
Is __________ kJ.

Accepted Answer

A) 67.6 
B) 45.5 
C) -293.8 
D) -45.5 
E) 293.8 
A) 67.6 
B) 45.5 
C) -293.8 
D) -45.5 
E) 293.8

Question 13

The temperature of a 12.58 g sample of calcium carbonate [CaCO3 (s)] increases from 23.6 °C to 38.2 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

Accepted Answer

A) 0.82 
B) 5.0 
C) 7.5 
D) 410 
E) 151 
A) 0.82 
B) 5.0 
C) 7.5 
D) 410 
E) 151

Question 14

The value of ΔH° for the reaction below is +128.1 kJ: CH3OH (l)→ CO (g)+ 2 H2 (g)
How many kJ of heat are consumed when 15.5 g of CH3OH (l)decomposes as shown in the equation?

Accepted Answer

A) 0.48 
B) 62.0 
C) 1.3 ×   
D) 32 
E) 8.3 
A) 0.48 
B) 62.0 
C) 1.3 ×   
D) 32 
E) 8.3

Question 15

Given the data in the table below, ΔH°rxn for the reaction 2 Ag2S (s)+ O2 (g)→ 2 Ag2O (s)+ 2S (s)
Is __________ kJ.

Accepted Answer

A) -1.6 
B) +1.6 
C) -3.2 
D) +3.2 
E) The ΔH°f of S (s)and of O2 (g)are needed for the calculation. 
A) -1.6 
B) +1.6 
C) -3.2 
D) +3.2 
E) The ΔH°f of S (s)and of O2 (g)are needed for the calculation.

Question 16

Which one of the following conditions would always result in an increase in the internal energy of a system?

Accepted Answer

A) The system loses heat and does work on the surroundings. 
B) The system gains heat and does work on the surroundings. 
C) The system loses heat and has work done on it by the surroundings. 
D) The system gains heat and has work done on it by the surroundings. 
E) None of the above is correct. 
A) The system loses heat and does work on the surroundings. 
B) The system gains heat and does work on the surroundings. 
C) The system loses heat and has work done on it by the surroundings. 
D) The system gains heat and has work done on it by the surroundings. 
E) None of the above is correct.

Question 17

Which one of the choices below is not considered a fossil fuel?

Accepted Answer

A) anthracite coal 
B) crude oil 
C) natural gas 
D) hydrogen 
E) petroleum 
A) anthracite coal 
B) crude oil 
C) natural gas 
D) hydrogen 
E) petroleum

Question 18

The average fuel value of sugars is 17 kJ/g. A 2.0 L pitcher of sweetened Kool-Aid contains 400 g of sugar. What is the fuel value (in kJ)of a 500 mL serving of Kool-Aid? (Assume that the sugar is the only fuel source.)

Accepted Answer

A) 4.2 × 104 
B) 1.7 × 103 
C) 1.7 × 106 
D) 1.7 × 102 
E) 17 
A) 4.2 × 104 
B) 1.7 × 103 
C) 1.7 × 106 
D) 1.7 × 102 
E) 17

Question 19

Given the data in the table below, ΔH°rxn for the reaction 3NO2 (g)+ H2O (l)→ 2HNO3 (aq)+ NO (g)
Is __________ kJ.

Accepted Answer

A) 64 
B) 140 
C) -140 
D) -508 
E) -64 
A) 64 
B) 140 
C) -140 
D) -508 
E) -64

Question 20

The internal energy of a system is always increased by __________.

Accepted Answer

A) adding heat to the system 
B) having the system do work on the surroundings 
C) withdrawing heat from the system 
D) adding heat to the system and having the system do work on the surroundings 
E) a volume compression 
A) adding heat to the system 
B) having the system do work on the surroundings 
C) withdrawing heat from the system 
D) adding heat to the system and having the system do work on the surroundings 
E) a volume compression

Exam 5: Thermochemistry

The value of ΔH° for the following reaction is -3351 kJ: 2Al (s)+ 3O2 (g)→ 2 Al2O3 (s) The value of ΔHf ° for Al2O3 (s)is __________ kJ.

The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ)released to the surroundings when 38.5 g of O2 (g)reacts with excess CO. 2CO (g)+ O2 (g)→ 2CO2 (g)

Given the data in the table below, ΔH°rxn for the reaction C2H5OH (l)+ O2 (g)→ CH3CO2H (l)+ H2O (l) Is __________ kJ.

The value of ΔH° for the reaction below is -186 kJ. H2 (g)+ Cl2 (g)→ 2HCl (g) The value of ΔHf° for HCl (g)is __________ kJ/mol.

The primary component of natural gas is propane.

ΔH for an endothermic process is __________ while ΔH for an exothermic process is __________.

For which one of the following reactions is the value of ΔH°rxn equal to ΔH°f for the product?

For the species in the reaction below, ΔHf° is zero for __________. 2Co (s)+ H2 (g)+ 8PF3 (g)→ 2HCo(PF3)4 (l)

The kinetic energy of a 10.3 g golf ball traveling at 48.0 m/s is __________ J.

Given the data in the table below, ΔH°rxn for the reaction IF5 (g)+ F2 (g)→ IF7 (g) Is __________ kJ.

Given the following reactions H2O (l)→ H2O (g)ΔH = 44.01 kJ 2 H2 (g)+ O2 (g)→ 2 H2O (g)ΔH = -483.64 kJ The enthalpy for the decomposition of liquid water into gaseous hydrogen and oxygen 2 H2O (l)→ 2 H2 (g)+ O2 (g) Is __________ kJ.

Given the following reactions N2 (g)+ O2 (g)→ 2NO (g)ΔH = +180.7 kJ 2NO (g)+ O2 (g)→ 2N O2 (g)ΔH = -113.1 kJ The enthalpy of reaction for 4NO (g)→ 2NO2 (g)+ N2 (g) Is __________ kJ.

The temperature of a 12.58 g sample of calcium carbonate [CaCO3 (s)] increases from 23.6 °C to 38.2 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

The value of ΔH° for the reaction below is +128.1 kJ: CH3OH (l)→ CO (g)+ 2 H2 (g) How many kJ of heat are consumed when 15.5 g of CH3OH (l)decomposes as shown in the equation?

Given the data in the table below, ΔH°rxn for the reaction 2 Ag2S (s)+ O2 (g)→ 2 Ag2O (s)+ 2S (s) Is __________ kJ.

Which one of the following conditions would always result in an increase in the internal energy of a system?

Which one of the choices below is not considered a fossil fuel?

The average fuel value of sugars is 17 kJ/g. A 2.0 L pitcher of sweetened Kool-Aid contains 400 g of sugar. What is the fuel value (in kJ)of a 500 mL serving of Kool-Aid? (Assume that the sugar is the only fuel source.)

Given the data in the table below, ΔH°rxn for the reaction 3NO2 (g)+ H2O (l)→ 2HNO3 (aq)+ NO (g) Is __________ kJ.

The internal energy of a system is always increased by __________.

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Stoichiometry: Calculations With Chemical Formulas and Equations

Aqueous Reactions and Solution Stoichiometry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Chemical Thermodynamics

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

Filters

The value of ΔH° for the following reaction is -3351 kJ: 2Al (s)+ 3O₂ (g)→ 2 Al₂O₃ (s) The value of ΔH_f ° for Al₂O₃ (s)is __________ kJ.

The value of ΔH° for the reaction below is -482 kJ. Calculate the heat (kJ)released to the surroundings when 38.5 g of O₂ (g)reacts with excess CO. 2CO (g)+ O₂ (g)→ 2CO₂ (g)

Given the data in the table below, ΔH°_rxn for the reaction C₂H₅OH (l)+ O₂ (g)→ CH₃CO₂H (l)+ H₂O (l) Is __________ kJ.

The value of ΔH° for the reaction below is -186 kJ. H₂ (g)+ Cl₂ (g)→ 2HCl (g) The value of ΔH_f° for HCl (g)is __________ kJ/mol.

ΔH for an endothermic process is while ΔH for an exothermic process is .

For which one of the following reactions is the value of ΔH°_rxn equal to ΔH°_f for the product?

For the species in the reaction below, ΔH_f° is zero for __________. 2Co (s)+ H₂ (g)+ 8PF₃ (g)→ 2HCo(PF₃)₄ (l)

Given the data in the table below, ΔH°_rxn for the reaction IF₅ (g)+ F₂ (g)→ IF₇ (g) Is __________ kJ.

Given the following reactions H₂O (l)→ H₂O (g)ΔH = 44.01 kJ 2 H₂ (g)+ O₂ (g)→ 2 H₂O (g)ΔH = -483.64 kJ The enthalpy for the decomposition of liquid water into gaseous hydrogen and oxygen 2 H₂O (l)→ 2 H₂ (g)+ O₂ (g) Is __________ kJ.

Given the following reactions N₂ (g)+ O₂ (g)→ 2NO (g)ΔH = +180.7 kJ 2NO (g)+ O₂ (g)→ 2N O₂ (g)ΔH = -113.1 kJ The enthalpy of reaction for 4NO (g)→ 2NO₂ (g)+ N₂ (g) Is __________ kJ.

The temperature of a 12.58 g sample of calcium carbonate [CaCO₃ (s)] increases from 23.6 °C to 38.2 °C. If the specific heat of calcium carbonate is 0.82 J/g-K, how many joules of heat are absorbed?

The value of ΔH° for the reaction below is +128.1 kJ: CH₃OH (l)→ CO (g)+ 2 H₂ (g) How many kJ of heat are consumed when 15.5 g of CH₃OH (l)decomposes as shown in the equation?

Given the data in the table below, ΔH°_rxn for the reaction 2 Ag₂S (s)+ O₂ (g)→ 2 Ag₂O (s)+ 2S (s) Is __________ kJ.

Given the data in the table below, ΔH°_rxn for the reaction 3NO₂ (g)+ H₂O (l)→ 2HNO₃ (aq)+ NO (g) Is __________ kJ.