Question 1

Choose the thermochemical equation that illustrates ΔH°f for Li2SO4.

Accepted Answer

A)  2 Li+(aq) + SO42-(aq) → Li2SO4(aq) 
B)  2 Li(s) + 1/8 S8(s, rhombic) + 2 O2(g) → Li2SO4(s) 
C)  Li2SO4(aq) → 2 Li+(aq) + SO42-(aq) 
D)  8 Li2SO4(s) → 16 Li(s) + S8(s, rhombic) + 16 O2(g) 
E)  16 Li(s) + S8(s, rhombic) + 16 O2(g) → 8 Li2SO4(s) 
A)  2 Li+(aq) + SO42-(aq) → Li2SO4(aq) 
B)  2 Li(s) + 1/8 S8(s, rhombic) + 2 O2(g) → Li2SO4(s) 
C)  Li2SO4(aq) → 2 Li+(aq) + SO42-(aq) 
D)  8 Li2SO4(s) → 16 Li(s) + S8(s, rhombic) + 16 O2(g) 
E)  16 Li(s) + S8(s, rhombic) + 16 O2(g) → 8 Li2SO4(s)

Question 2

For a process at constant pressure,49,600 calories of heat are released.This quantity of heat is equivalent to

Accepted Answer

A)  4.82 × 10-6 J. 
B)  1.19 × 104 J. 
C)  1.24 × 104 J. 
D)  2.08 × 105 J. 
A)  4.82 × 10-6 J. 
B)  1.19 × 104 J. 
C)  1.24 × 104 J. 
D)  2.08 × 105 J.

Question 3

For the reaction: NO(g)+ 1/2 O2(g)→ NO2(g)
ΔH°rxn is -114.14 kJ/mol.Calculate ΔH°f of gaseous nitrogen monoxide,given that ΔH°f of NO2(g)is 33.90 kJ/mol.

Accepted Answer

A)  148.0 kJ/mol 
B)  91.04 kJ/mol 
C)  -114.1 kJ/mol 
D)  181.9 kJ/mol 
E)  -35.64 kJ/mol 
A)  148.0 kJ/mol 
B)  91.04 kJ/mol 
C)  -114.1 kJ/mol 
D)  181.9 kJ/mol 
E)  -35.64 kJ/mol

Question 4

Using the following thermochemical equation,determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6). 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

Accepted Answer

A)  1.43 × 105 kJ/kg CO2 
B)  2.30 × 104 kJ/kg CO2 
C)  4.34 × 104 kJ/kg CO2 
D)  1.19 × 104 kJ/kg CO2 
E)  8.40 × 105 kJ/kg CO2 
A)  1.43 × 105 kJ/kg CO2 
B)  2.30 × 104 kJ/kg CO2 
C)  4.34 × 104 kJ/kg CO2 
D)  1.19 × 104 kJ/kg CO2 
E)  8.40 × 105 kJ/kg CO2

Question 5

Describe the energy changes that occur when a book is held 6 ft off the floor and then dropped.

Accepted Answer

The book starts out with a cer

Question 6

According to the following reaction,how much energy is evolved during the reaction of 32.5 g B2H6 and 72.5 g Cl2? The molar mass of B2H6 is 27.67 g/mol.
B2H6(g)+ 6 Cl2(g)→ 2 BCl3(g)+ 6 HCl(g)ΔH°rxn = -1396 kJ

Accepted Answer

A)  1640 kJ 
B)  238 kJ 
C)  1430 kJ 
D)  3070 kJ 
E)  429 kJ 
A)  1640 kJ 
B)  238 kJ 
C)  1430 kJ 
D)  3070 kJ 
E)  429 kJ

Question 7

A 6.50-g sample of copper metal at 25.0°C is heated by the addition of 84.0 J of energy.The final temperature of the copper is ________°C.The specific heat capacity of copper is

Accepted Answer

A)  29.9 
B)  25.0 
C)  9.0 
D)  59.0 
E)  34.0 
A)  29.9 
B)  25.0 
C)  9.0 
D)  59.0 
E)  34.0

Question 8

How much energy is required to decompose 612 g of PCl3,according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful.
4 PCl3(g)→ P4(s)+ 6 Cl2(g)ΔH°rxn = +1207 kJ

Accepted Answer

A)  1.85 × 103 kJ 
B)  3.46 × 103 kJ 
C)  5.38 × 103 kJ 
D)  1.34 × 103 kJ 
E)  4.76 × 103 kJ 
A)  1.85 × 103 kJ 
B)  3.46 × 103 kJ 
C)  5.38 × 103 kJ 
D)  1.34 × 103 kJ 
E)  4.76 × 103 kJ

Question 9

According to the following reaction,how much energy is required to decompose 59.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g/mol.
Fe3O4(s)→ 3 Fe(s)+ 2 O2(g)ΔH°rxn = +1118 kJ

Accepted Answer

A)  1.42 × 105 kJ 
B)  1.13 × 104 kJ 
C)  2.85 × 105 kJ 
D)  5.70 × 105 kJ 
E)  8.55 × 105 kJ 
A)  1.42 × 105 kJ 
B)  1.13 × 104 kJ 
C)  2.85 × 105 kJ 
D)  5.70 × 105 kJ 
E)  8.55 × 105 kJ

Question 10

Use the bond energies provided to estimate ΔH°rxn for the reaction below. 2 Br2(l)+ C2H2(g)→ C2H2Br4(l)ΔH°rxn = ?
Bond Bond Energy (kJ/mol)
Br-Br 193
C≡C 837
C-C 347
C-Br 276
C-H 414

Accepted Answer

A)  +407 kJ 
B)  -324 kJ 
C)  -228 kJ 
D)  +573 kJ 
E)  -648 kJ 
A)  +407 kJ 
B)  -324 kJ 
C)  -228 kJ 
D)  +573 kJ 
E)  -648 kJ

Question 11

At constant pressure,the combustion of 15.0 g of C2H6(g)releases 777 kJ of heat.What is ΔH for the reaction given below?
2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

Accepted Answer

A)  -129 kJ 
B)  -779 kJ 
C)  -1560 kJ 
D)  -3120 kJ 
A)  -129 kJ 
B)  -779 kJ 
C)  -1560 kJ 
D)  -3120 kJ

Question 12

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 24.3 g benzene (C6H6).The molar mass of benzene is 78.11 g/mole. 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

Accepted Answer

A)  3910 kJ 
B)  1950 kJ 
C)  977 kJ 
D)  40.1 kJ 
E)  0.302 kJ 
A)  3910 kJ 
B)  1950 kJ 
C)  977 kJ 
D)  40.1 kJ 
E)  0.302 kJ

Question 13

A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HNO3 in a coffee cup calorimeter.If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C,determine the ΔH°rxn (in units of kJ/mol NaOH)for the neutralization reaction between aqueous NaOH and HCl.Assume 1)that no heat is lost to the calorimeter or the surroundings,and 2)that the density and the heat capacity of the resulting solution are the same as water.

Accepted Answer

A)  -55.7 kJ/mol NaOH 
B)  -169 kJ/mol NaOH 
C)  -16.7 kJ/mol NaOH 
D)  -27.9 kJ/mol NaOH 
E)  - 34.4 kJ/mol NaOH 
A)  -55.7 kJ/mol NaOH 
B)  -169 kJ/mol NaOH 
C)  -16.7 kJ/mol NaOH 
D)  -27.9 kJ/mol NaOH 
E)  - 34.4 kJ/mol NaOH

Question 14

Which of the following statements about energy is FALSE?

Accepted Answer

A)  Energy can be converted from one type to another. 
B)  The total energy of a system remains constant. 
C)  Kinetic energy is the energy associated with its position or composition. 
D)  Energy is the capacity to do work. 
E)  Systems tend to change in order to lower their potential energy. 
A)  Energy can be converted from one type to another. 
B)  The total energy of a system remains constant. 
C)  Kinetic energy is the energy associated with its position or composition. 
D)  Energy is the capacity to do work. 
E)  Systems tend to change in order to lower their potential energy.

Question 15

A 43.9-g piece of copper (CCu= 0.385 J/g°C)at 135.0°C is plunged into 254 g of water at 39.0°C.Assuming that no heat is lost to the surroundings,what will the final temperature of the system be?

Accepted Answer

A)  100.0°C 
B)  40.5°C 
C)  62.5°C 
D)  87.0°C 
E)  53.1°C 
A)  100.0°C 
B)  40.5°C 
C)  62.5°C 
D)  87.0°C 
E)  53.1°C

Question 16

Use the ΔH°f information provided to calculate ΔH°rxn for the following ΔH°f (kJ/mol) SO2Cl2(g)+ 2 H2O(l)→ 2 HCl(g)+ H2SO4(l)ΔH°rxn = ?
SO2Cl2(g)-364
H2O(l)-286
HCl(g)-92
H2SO4(l)-814

Accepted Answer

A)  -256 kJ 
B)  +161 kJ 
C)  -62 kJ 
D)  +800. kJ 
E)  -422 kJ 
A)  -256 kJ 
B)  +161 kJ 
C)  -62 kJ 
D)  +800. kJ 
E)  -422 kJ

Question 17

Match between columns
                        Premises: energy associated with the relative positions of electrons and nuclei in atoms and molecules
energy associated with the motion of an object
energy associated with the temperature of an object
energy associated with the position of an object
-ΔE

Accepted Answer

The Answer of potential energy and thermal energy and chemical is...

Question 18

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction 4 SO3(g)→ 4 S(s)+ 6 O2(g)ΔH°rxn = ?
Given:
SO2(g)→ S(s)+ O2(g)ΔH°rxn = +296.8 kJ
2 SO2(g)+ O2(g)→ 2 SO3(g)ΔH°rxn = -197.8 kJ

Accepted Answer

A)  -494.6 kJ 
B)  -692.4 kJ 
C)  -791.4 kJ 
D)  1583 kJ 
E)  -293.0 kJ 
A)  -494.6 kJ 
B)  -692.4 kJ 
C)  -791.4 kJ 
D)  1583 kJ 
E)  -293.0 kJ

Question 19

Give the equation with the elements in MgSO4 in their standard state as the reactants and MgSO4 as the product.

Accepted Answer

Mg(s)+ 1/8

Question 20

Identify a substance that is in its standard state.

Accepted Answer

A)  N2(l) 
B)  Cu(g) 
C)  Cl 
D)  He2 
E)  Br(l) 
A)  N2(l) 
B)  Cu(g) 
C)  Cl 
D)  He2 
E)  Br(l)

Exam 10: Thermochemistry

Choose the thermochemical equation that illustrates ΔH°f for Li2SO4.

For a process at constant pressure,49,600 calories of heat are released.This quantity of heat is equivalent to

For the reaction: NO(g)+ 1/2 O2(g)→ NO2(g) ΔH°rxn is -114.14 kJ/mol.Calculate ΔH°f of gaseous nitrogen monoxide,given that ΔH°f of NO2(g)is 33.90 kJ/mol.

Using the following thermochemical equation,determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6). 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

Describe the energy changes that occur when a book is held 6 ft off the floor and then dropped.

According to the following reaction,how much energy is evolved during the reaction of 32.5 g B2H6 and 72.5 g Cl2? The molar mass of B2H6 is 27.67 g/mol. B2H6(g)+ 6 Cl2(g)→ 2 BCl3(g)+ 6 HCl(g)ΔH°rxn = -1396 kJ

A 6.50-g sample of copper metal at 25.0°C is heated by the addition of 84.0 J of energy.The final temperature of the copper is ________°C.The specific heat capacity of copper is

How much energy is required to decompose 612 g of PCl3,according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful. 4 PCl3(g)→ P4(s)+ 6 Cl2(g)ΔH°rxn = +1207 kJ

According to the following reaction,how much energy is required to decompose 59.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g/mol. Fe3O4(s)→ 3 Fe(s)+ 2 O2(g)ΔH°rxn = +1118 kJ

Use the bond energies provided to estimate ΔH°rxn for the reaction below. 2 Br2(l)+ C2H2(g)→ C2H2Br4(l)ΔH°rxn = ? Bond Bond Energy (kJ/mol) Br-Br 193 C≡C 837 C-C 347 C-Br 276 C-H 414

At constant pressure,the combustion of 15.0 g of C2H6(g)releases 777 kJ of heat.What is ΔH for the reaction given below? 2 C2H6(g)+ 7 O2(g)→ 4 CO2(g)+ 6 H2O(l)

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 24.3 g benzene (C6H6).The molar mass of benzene is 78.11 g/mole. 2 C6H6(l)+ 15 O2(g)→ 12 CO2(g)+ 6 H2O(g)ΔH°rxn = -6278 kJ

Which of the following statements about energy is FALSE?

A 43.9-g piece of copper (CCu= 0.385 J/g°C)at 135.0°C is plunged into 254 g of water at 39.0°C.Assuming that no heat is lost to the surroundings,what will the final temperature of the system be?

Use the ΔH°f information provided to calculate ΔH°rxn for the following ΔH°f (kJ/mol) SO2Cl2(g)+ 2 H2O(l)→ 2 HCl(g)+ H2SO4(l)ΔH°rxn = ? SO2Cl2(g)-364 H2O(l)-286 HCl(g)-92 H2SO4(l)-814

Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction 4 SO3(g)→ 4 S(s)+ 6 O2(g)ΔH°rxn = ? Given: SO2(g)→ S(s)+ O2(g)ΔH°rxn = +296.8 kJ 2 SO2(g)+ O2(g)→ 2 SO3(g)ΔH°rxn = -197.8 kJ

Give the equation with the elements in MgSO4 in their standard state as the reactants and MgSO4 as the product.

Identify a substance that is in its standard state.

Essentials: Units, Measurements, and Problem Solving

Atoms

The Quantum Mechanical Model of the Atom

Periodic Properties of the Elements

Molecules and Compounds

Chemical Bonding I

Chemical Bonding Ii

Chemical Reactions and Chemical Quantities

Introduction to Solutions and Aqueous Reactions

Gases

Liquids, Solids, and Intermolecular Forces

Crystalline Solids and Modern Materials

Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Free Energy and Thermodynamics

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry

Transition Metals and Coordination Compounds

Filters

Choose the thermochemical equation that illustrates ΔH°_f for Li₂SO₄.

For the reaction: NO(g)+ 1/2 O₂(g)→ NO₂(g) ΔH°_rxnis -114.14 kJ/mol.Calculate ΔH°_f of gaseous nitrogen monoxide,given that ΔH°_fof NO₂(g)is 33.90 kJ/mol.

Using the following thermochemical equation,determine the amount of heat produced per kg of CO₂ formed during the combustion of benzene (C₆H₆). 2 C₆H₆(l)+ 15 O₂(g)→ 12 CO₂(g)+ 6 H₂O(g)ΔH°_rxn= -6278 kJ

According to the following reaction,how much energy is evolved during the reaction of 32.5 g B₂H₆ and 72.5 g Cl₂? The molar mass of B₂H₆is 27.67 g/mol. B₂H₆(g)+ 6 Cl₂(g)→ 2 BCl₃(g)+ 6 HCl(g)ΔH°_rxn= -1396 kJ

How much energy is required to decompose 612 g of PCl₃,according to the reaction below? The molar mass of PCl₃ is 137.32 g/mol and may be useful. 4 PCl₃(g)→ P₄(s)+ 6 Cl₂(g)ΔH°_rxn = +1207 kJ

According to the following reaction,how much energy is required to decompose 59.0 kg of Fe₃O₄? The molar mass of Fe₃O₄is 231.55 g/mol. Fe₃O₄(s)→ 3 Fe(s)+ 2 O₂(g)ΔH°_rxn= +1118 kJ

Use the bond energies provided to estimate ΔH°_rxn for the reaction below. 2 Br₂(l)+ C₂H₂(g)→ C₂H₂Br₄(l)ΔH°_rxn= ? Bond Bond Energy (kJ/mol) Br-Br 193 C≡C 837 C-C 347 C-Br 276 C-H 414

At constant pressure,the combustion of 15.0 g of C₂H₆(g)releases 777 kJ of heat.What is ΔH for the reaction given below? 2 C₂H₆(g)+ 7 O₂(g)→ 4 CO₂(g)+ 6 H₂O(l)

Using the following thermochemical equation,determine the amount of heat produced from the combustion of 24.3 g benzene (C₆H₆).The molar mass of benzene is 78.11 g/mole. 2 C₆H₆(l)+ 15 O₂(g)→ 12 CO₂(g)+ 6 H₂O(g)ΔH°_rxn= -6278 kJ

A 43.9-g piece of copper (C_Cu= 0.385 J/g°C)at 135.0°C is plunged into 254 g of water at 39.0°C.Assuming that no heat is lost to the surroundings,what will the final temperature of the system be?

Use the ΔH°_f information provided to calculate ΔH°_rxn for the following ΔH°_{f (kJ/mol)} SO₂Cl₂(g)+ 2 H₂O(l)→ 2 HCl(g)+ H₂SO4(l)ΔH°_rxn= ? SO₂Cl₂(g)-364 H₂O(l)-286 HCl(g)-92 H₂SO₄(l)-814

Use the standard reaction enthalpies given below to determine ΔH°_rxn for the following reaction 4 SO₃(g)→ 4 S(s)+ 6 O₂(g)ΔH°_rxn= ? Given: SO₂(g)→ S(s)+ O₂(g)ΔH°_rxn= +296.8 kJ 2 SO₂(g)+ O₂(g)→ 2 SO₃(g)ΔH°_rxn= -197.8 kJ

Give the equation with the elements in MgSO₄ in their standard state as the reactants and MgSO₄ as the product.