Question 1

Given that CaO(s) + H2O(l) $\rarr$ Ca(OH)2(s), $\Delta$H$\circ$rxn = -64.8 kJ/mol, how many grams of CaO must react in order to liberate 525 kJ of heat

Accepted Answer

A)  6.92 g 
B)  56.1 g 
C)  455 g 
D)  606 g 
E)  3.40 * 104 g 
A)  6.92 g 
B)  56.1 g 
C)  455 g 
D)  606 g 
E)  3.40 * 104 g

Question 2

For which of these reactions will the difference between $\Delta$H$\circ$ and $\Delta$E$\circ$ be the smallest

Accepted Answer

A)  N2(g) + 3H2(g) $\rarr$ 2NH3(g) 
B)  4PH3(g) $\rarr$ P4(g) + 6H2(g) 
C)  H2(g) + Cl2(g) $\rarr$ 2HCl(g) 
D)  CO2(g) + 2H2O(l) $\rarr$ CH4(g) + 2O2(g) 
E)  P4(s) + 10Cl2(g) $\rarr$ 4PCl5(s) 
A)  N2(g) + 3H2(g) $\rarr$ 2NH3(g) 
B)  4PH3(g) $\rarr$ P4(g) + 6H2(g) 
C)  H2(g) + Cl2(g) $\rarr$ 2HCl(g) 
D)  CO2(g) + 2H2O(l) $\rarr$ CH4(g) + 2O2(g) 
E)  P4(s) + 10Cl2(g) $\rarr$ 4PCl5(s)

Question 3

Specific heat is defined as the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.

Accepted Answer

A) True 
 B)False

Question 4

Styrene, C8H8, is one of the substances used in the production of synthetic rubber. When styrene burns in oxygen to form carbon dioxide and liquid water under standard-state conditions at 25$\circ$C, 42.62 kJ are released per gram of styrene. Find the standard enthalpy of formation of styrene at 25$\circ$C.(Given: $\Delta$H$\circ$f[CO2(g)] = -393.5 kJ/mol, $\Delta$H$\circ$f[H2O(l)] = -285.8 kJ/mol, $\Delta$H$\circ$f[H2O(g)] = -241.8 kJ/mol)

Accepted Answer

A)  147.8 kJ/mol 
B)  323.8 kJ/mol 
C)  ~636.7 kJ/mol 
D)  ~4249 kJ/mol 
E)  ~8730 kJ/mol 
A)  147.8 kJ/mol 
B)  323.8 kJ/mol 
C)  ~636.7 kJ/mol 
D)  ~4249 kJ/mol 
E)  ~8730 kJ/mol

Question 5

An average home in Colorado requires 20. GJ of heat per month. How many grams of natural gas (methane) must be burned to supply this energy
CH4(g) + 2O2(g) $\rarr$ CO2(g) + 2H2O(l) $\Delta$H$\circ$rxn= -890.4 kJ/mol

Accepted Answer

A)  7.1 * 10-4 g 
B)  1.4 * 103 g 
C)  1.4 * 104 g 
D)  2.2 * 104 g 
E)  3.6 * 105 g 
A)  7.1 * 10-4 g 
B)  1.4 * 103 g 
C)  1.4 * 104 g 
D)  2.2 * 104 g 
E)  3.6 * 105 g

Question 6

When 0.560 g of Na(s) reacts with excess F2(g) to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ($\Delta$H$\circ$f) of NaF(s)

Accepted Answer

A)  -570 kJ/mol 
B)  -24.8 kJ/mol 
C)  -7.8 kJ/mol 
D)  24.8 kJ/mol 
E)  570 kJ/mol 
A)  -570 kJ/mol 
B)  -24.8 kJ/mol 
C)  -7.8 kJ/mol 
D)  24.8 kJ/mol 
E)  570 kJ/mol

Question 7

A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/$\circ$C. What is the specific heat of copper

Accepted Answer

A)  0.385 J/g·$\circ$C 
B)  1.32 J/g·$\circ$C 
C)  2.60 J/g·$\circ$C 
D)  24.5 J/g·$\circ$C 
E)  1.83 * 104 J/g·$\circ$C 
A)  0.385 J/g·$\circ$C 
B)  1.32 J/g·$\circ$C 
C)  2.60 J/g·$\circ$C 
D)  24.5 J/g·$\circ$C 
E)  1.83 * 104 J/g·$\circ$C

Question 8

The work done on the surroundings by the expansion of a gas is w = -PDV.

Accepted Answer

A) True 
 B)False

Question 9

The heat of solution of calcium chloride CaCl2 is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ. What is the lattice energy of calcium chloride

Accepted Answer

A)  2,144 kJ/mol 
B)  2,244 kJ/mol 
C)  2,344 kJ/mol 
D)  2,444 kJ/mol 
E)  None of the above 
A)  2,144 kJ/mol 
B)  2,244 kJ/mol 
C)  2,344 kJ/mol 
D)  2,444 kJ/mol 
E)  None of the above

Question 10

The heat capacity of 10.0 g of water is 83.7 J/$\circ$C.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following has a $\Delta$H$\circ$f= 0 kJ/mol

Accepted Answer

A)  CO2(g) 
B)  O3(g) 
C)  Cl-(aq) 
D)  NH3(aq) 
E)  I2(s) 
A)  CO2(g) 
B)  O3(g) 
C)  Cl-(aq) 
D)  NH3(aq) 
E)  I2(s)

Question 12

Given the thermochemical equation 2SO2(g) + O2(g) $\rarr$ 2SO3(g), $\Delta$H$\circ$rxn= -198 kJ/mol, how much heat is evolved when 600. g of SO2 is burned

Accepted Answer

A)  5.46 * 10-2 kJ 
B)  928 kJ 
C)  1.85 * 103 kJ 
D)  3.71 * 103 kJ 
E)  59,400 kJ 
A)  5.46 * 10-2 kJ 
B)  928 kJ 
C)  1.85 * 103 kJ 
D)  3.71 * 103 kJ 
E)  59,400 kJ

Question 13

The heat of combustion of propane, C3H8, is 2220 kJ/mol. The specific heat of copper is 0.385 J/g*$\circ$C. How many grams of propane must be burned to raise the temperature of a 10.0 kg block of copper from 25.0$\circ$C to 65.0$\circ$C, assuming none of the heat is lost to the surroundings

Accepted Answer

A)  3.36 g 
B)  3.26 g 
C)  3.16 g 
D)  3.06 g 
E)  None of the above 
A)  3.36 g 
B)  3.26 g 
C)  3.16 g 
D)  3.06 g 
E)  None of the above

Question 14

A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0 atm. Calculate the amount of work done on the system.

Accepted Answer

A)  -1.81 * 104 J 
B)  -180 J 
C)  180 J 
D)  1.01 * 104 J 
E)  1.81 * 104 J 
A)  -1.81 * 104 J 
B)  -180 J 
C)  180 J 
D)  1.01 * 104 J 
E)  1.81 * 104 J

Question 15

A 135 g sample of H2O at 85$\circ$C is cooled. The water loses a total of 15 kJ of energy in the cooling process. What is the final temperature of the water The specific heat of water is 4.184 J/g·$\circ$C.

Accepted Answer

A)  27$\circ$C 
B)  58$\circ$C 
C)  70$\circ$C 
D)  84$\circ$C 
E)  112$\circ$C 
A)  27$\circ$C 
B)  58$\circ$C 
C)  70$\circ$C 
D)  84$\circ$C 
E)  112$\circ$C

Question 16

When an automobile engine starts, the metal parts immediately begin to absorb heat released during the combustion of gasoline. How much heat will be absorbed by a 165 kg iron engine block as the temperature rises from 15.7$\circ$C to 95.7$\circ$C (The specific heat of iron is 0.489 J/g·$\circ$C.)

Accepted Answer

A)  6,450 kJ 
B)  6,350 kJ 
C)  6,250 kJ 
D)  6,150 kJ 
E)  None of the above 
A)  6,450 kJ 
B)  6,350 kJ 
C)  6,250 kJ 
D)  6,150 kJ 
E)  None of the above

Question 17

At 25$\circ$C, the following heats of reaction are known: $\begin{array}{ll}
2 \mathrm{ClF}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{Cl}_{2} \mathrm{O}(\mathrm{~g})+\mathrm{F}_{2} \mathrm{O}(\mathrm{~g}) & \Delta \mathrm{H}_{\mathrm{rxn}}^{\circ}=167.4 \mathrm{~kJ} / \mathrm{mol} \
2 \mathrm{ClF}_{3}(\mathrm{~g})+2 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{Cl}_{2} \mathrm{O}(\mathrm{~g})+3 \mathrm{~F}_{2} \mathrm{O}(\mathrm{~g}) & \Delta \mathrm{H}_{\mathrm{rxn}}^{\circ}=341.4 \mathrm{~kJ} / \mathrm{mol} \
2 \mathrm{~F}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{~F}_{2} \mathrm{O}(\mathrm{~g}) & \Delta \mathrm{H}_{\mathrm{rxn}}^{\circ}=-43.4 \mathrm{~kJ} / \mathrm{mol}
\end{array}$ At the same temperature, use the above data to calculate the heat released (kJ) when 3.40 moles of ClF(g) reacts with excess F2: ClF(g) + F2(g) $\rarr$ ClF3(g)

Accepted Answer

A)  109 kJ 
B)  233 kJ 
C)  370. kJ 
D)  465 kJ 
E)  1,580 kJ 
A)  109 kJ 
B)  233 kJ 
C)  370. kJ 
D)  465 kJ 
E)  1,580 kJ

Question 18

The heat of solution of KCl is 17.2 kJ/mol and the lattice energy of KCl(s) is 701.2 kJ/mol. Calculate the total heat of hydration of 1.00 mol of gas phase K+ ions and Cl- ions.

Accepted Answer

A)  -718 kJ 
B)  -684 kJ 
C)  684 kJ 
D)  718 kJ 
E)  None of these. 
A)  -718 kJ 
B)  -684 kJ 
C)  684 kJ 
D)  718 kJ 
E)  None of these.

Question 19

Calculate the heat released (kJ) in the reaction of 3.50 g of acetylene (C2H2) and excess hydrogen gas to form ethane gas: C2H2(g) + 2H2(g) $\rarr$C2H6(g)
Given:
2C2H2(g) + 5O2(g) $\rarr$ 4CO2(g) + 2H2O(g) $\Delta$H = -2320 kJ/mol
2C2H6(g) + 7O2(g) $\rarr$ 4CO2(g) + 6H2O(g) $\Delta$H = -3040 kJ/mol
2H2(g) + O2(g) $\rarr$ 2H2O(g) $\Delta$H = -572 kJ/mol

Accepted Answer

A)  27.5 kJ 
B)  28.5 kJ 
C)  29.5 kJ 
D)  30.5 kJ 
E)  None of the above 
A)  27.5 kJ 
B)  28.5 kJ 
C)  29.5 kJ 
D)  30.5 kJ 
E)  None of the above

Question 20

Chemical energy is

Accepted Answer

A)  the energy stored within the structural units of chemical substances. 
B)  the energy associated with the random motion of atoms and molecules. 
C)  solar energy, i.e. energy that comes from the sun. 
D)  energy available by virtue of an object's position. 
A)  the energy stored within the structural units of chemical substances. 
B)  the energy associated with the random motion of atoms and molecules. 
C)  solar energy, i.e. energy that comes from the sun. 
D)  energy available by virtue of an object's position.

Exam 6: Thermochemistry

Given that CaO(s) + H2O(l) →\rarr→ Ca(OH)2(s), Δ\DeltaΔ H ∘\circ∘ rxn = -64.8 kJ/mol, how many grams of CaO must react in order to liberate 525 kJ of heat

For which of these reactions will the difference between Δ\DeltaΔ H ∘\circ∘ and Δ\DeltaΔ E ∘\circ∘ be the smallest

Specific heat is defined as the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.

An average home in Colorado requires 20. GJ of heat per month. How many grams of natural gas (methane) must be burned to supply this energy CH4(g) + 2O2(g) →\rarr→ CO2(g) + 2H2O(l) Δ\DeltaΔ H ∘\circ∘ rxn= -890.4 kJ/mol

When 0.560 g of Na(s) reacts with excess F2(g) to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ( Δ\DeltaΔ H ∘\circ∘ f) of NaF(s)

A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/ ∘\circ∘ C. What is the specific heat of copper

The work done on the surroundings by the expansion of a gas is w = -PDV.

The heat of solution of calcium chloride CaCl2 is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ. What is the lattice energy of calcium chloride

The heat capacity of 10.0 g of water is 83.7 J/ ∘\circ∘ C.

Which of the following has a Δ\DeltaΔ H ∘\circ∘ f= 0 kJ/mol

Given the thermochemical equation 2SO2(g) + O2(g) →\rarr→ 2SO3(g), Δ\DeltaΔ H ∘\circ∘ rxn= -198 kJ/mol, how much heat is evolved when 600. g of SO2 is burned

A gas is compressed in a cylinder from a volume of 20.0 L to 2.0 L by a constant pressure of 10.0 atm. Calculate the amount of work done on the system.

A 135 g sample of H2O at 85 ∘\circ∘ C is cooled. The water loses a total of 15 kJ of energy in the cooling process. What is the final temperature of the water The specific heat of water is 4.184 J/g· ∘\circ∘ C.

The heat of solution of KCl is 17.2 kJ/mol and the lattice energy of KCl(s) is 701.2 kJ/mol. Calculate the total heat of hydration of 1.00 mol of gas phase K+ ions and Cl- ions.

Chemical energy is

Chemistry: The Study of Change

Atoms Molecules and Ions

Mass Relationships in Chemical Reactions

Reactions in Aqueous Solutions

Gases

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Entropy Free Energy and Equilibrium

Electrochemistry

Nuclear Chemistry

Chemistry in the Atmosphere

Metallurgy and the Chemistry of Metals

Nonmetallic Elements and Their Compounds

Transition Metals Chemistry and Coordination Compounds

Organic Chemistry

Synthetic and Natural Organic Polymers

Filters

Given that CaO(s) + H₂O(l) $\rarr$ Ca(OH)₂(s), $\Delta$ H^$\circ$_rxn = -64.8 kJ/mol, how many grams of CaO must react in order to liberate 525 kJ of heat

For which of these reactions will the difference between $\Delta$ H^$\circ$ and $\Delta$ E^$\circ$ be the smallest

An average home in Colorado requires 20. GJ of heat per month. How many grams of natural gas (methane) must be burned to supply this energy CH₄(g) + 2O₂(g) $\rarr$ CO₂(g) + 2H₂O(l) $\Delta$ H^$\circ$_rxn= -890.4 kJ/mol

When 0.560 g of Na(s) reacts with excess F₂(g) to form NaF(s), 13.8 kJ of heat is evolved at standard-state conditions. What is the standard enthalpy of formation ( $\Delta$ H^$\circ$_f) of NaF(s)

A piece of copper with a mass of 218 g has a heat capacity of 83.9 J/^$\circ$C. What is the specific heat of copper

The heat of solution of calcium chloride CaCl₂ is -82.8 kJ/mol, and the combined heats of hydration of 1.00 mole of gaseous calcium ions and 2.00 mole of gaseous chloride ions is -2327 kJ. What is the lattice energy of calcium chloride

The heat capacity of 10.0 g of water is 83.7 J/^$\circ$C.

Which of the following has a $\Delta$ H^$\circ$_f= 0 kJ/mol

Given the thermochemical equation 2SO₂(g) + O₂(g) $\rarr$ 2SO₃(g), $\Delta$ H^$\circ$_rxn= -198 kJ/mol, how much heat is evolved when 600. g of SO₂ is burned

A 135 g sample of H₂O at 85^$\circ$C is cooled. The water loses a total of 15 kJ of energy in the cooling process. What is the final temperature of the water The specific heat of water is 4.184 J/g·^$\circ$C.

The heat of solution of KCl is 17.2 kJ/mol and the lattice energy of KCl(s) is 701.2 kJ/mol. Calculate the total heat of hydration of 1.00 mol of gas phase K⁺ ions and Cl^- ions.