Question 1

15.0 g of ice cubes at 0.0 °\degree° C are combined with 150. g of liquid water at 70.0 °\degree° C in a coffee cup calorimeter. Calculate the final temperature reached, assuming no heat loss or gain from the surroundings. (Data: specific heat capacity of H2O(l) , c = 4.18 J/g* °\degree° C; H2O(s)   →\rightarrow→  H2O(l)   Δ\DeltaΔ H = 6.02 kJ/mol)

Accepted Answer

A)   0.0
B)   10.6
C)   30.7
D)   43.2
E)   56.4 F) C) and E)
G) D) and E)

Question 2

Which one of the following relationships is always correct?

Accepted Answer

A)   potential energy + kinetic energy = constant
B)   E = q + w
C)   ( Δ\DeltaΔ E =  Δ\DeltaΔ H - P  Δ\DeltaΔ V) 
D)   H = E + PV
E)   ( Δ\DeltaΔ H = qv)  F) A) and B)
G) A) and C)

Question 3

Calculate the  Δ\DeltaΔ H °\degree° rxn for the following reaction. ( Δ\DeltaΔ H °\degree° f [AsH3(g) ] = 66.4 kJ/mol;  Δ\DeltaΔ H °\degree° f [H3AsO4(aq) ] = -904.6 kJ/mol;  Δ\DeltaΔ H °\degree° f [H2O(l) ] = -285.8 kJ/mol)  rxn for the following reaction. ( \Delta H \degree f [AsH3(g) ] = 66.4 kJ/mol;  \Delta H \degree f [H3AsO4(aq) ] = -904.6 kJ/mol;  \Delta H \degree f [H2O(l) ] = -285.8 kJ/mol)    A)  -1981.4 kJ B)  -685.2 kJ C)  -172.2 kJ D)  172.2 kJ E)  685.2 kJ " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -1981.4 kJ
B)   -685.2 kJ
C)   -172.2 kJ
D)   172.2 kJ
E)   685.2 kJ F) A) and D)
G) None of the above

Question 4

Use the following data to calculate the standard heat (enthalpy)  of formation,  Δ\DeltaΔ Hf, of manganese(IV)  oxide, MnO2 (s) . f, of manganese(IV)  oxide, MnO2 (s) .   A)  -504 kJ B)  -372 kJ C)  -24 kJ D)  24 kJ E)  504 kJ " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -504 kJ
B)   -372 kJ
C)   -24 kJ
D)   24 kJ
E)   504 kJ F) B) and E)
G) C) and E)

Question 5

A system that does no work but which transfers heat to the surroundings has:

Accepted Answer

A)   q Δ\DeltaΔ E > 0
B)   q Δ\DeltaΔ E 
C)   q > 0,  Δ\DeltaΔ E > 0
D)   q > 0,  Δ\DeltaΔ E 
E)   q Δ\DeltaΔ E = 0 F) B) and D)
G) B) and E)

Question 6

In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Accepted Answer

A) True 
 B)False

Question 7

Ethanol, C2H5OH, is being promoted as a clean fuel and is used as an additive in many gasoline mixtures. Calculate the  Δ\DeltaΔ H °\degree° rxn for the combustion of ethanol. ( Δ\DeltaΔ H °\degree° f [C2H5OH(l) ] = -277.7 kJ/mol;  Δ\DeltaΔ H °\degree° f [CO2(g) ] = -393.5 kJ/mol;  Δ\DeltaΔ H °\degree° f [H2O(g) ] = -241.8 kJ/mol)

Accepted Answer

A)   -1234.7 kJ
B)   -751.1 kJ
C)   -357.6 kJ
D)   357.6 kJ
E)   1234.7 kJ F) D) and E)
G) B) and C)

Question 8

Stoichiometric amounts of nitrogen gas and hydrogen gas react in a calorimeter to produce 5.00 g of ammonia gas. The calorimeter temperature rises 0.42 °\degree° C. The calorimeter and water have a combined heat capacity of 32.16 kJ/K. Calculate the heat of formation of ammonia,  Δ\DeltaΔ Hf °\degree° , in kJ/mol. The formation reaction for ammonia is: f \degree , in kJ/mol. The formation reaction for ammonia is:   A)  -46 kJ/mol B)  -13.5 kJ/mol C)  -3.97 kJ/mol D)  3.97 kJ/mol E)  13.5 kJ/mol " class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   -46 kJ/mol
B)   -13.5 kJ/mol
C)   -3.97 kJ/mol
D)   3.97 kJ/mol
E)   13.5 kJ/mol F) A) and E)
G) None of the above

Question 9

In a reaction with high energy reactants and low energy products, q is negative.

Accepted Answer

A) True 
 B)False

Question 10

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Accepted Answer

A)   1.92 *10¯1 kcal
B)   1.92 * 102 kcal
C)   3.36 * 103 kcal
D)   1.92 *105 kcal
E)   3.36 * 106 kcalF) A) and E)
G) A) and D)

Question 11

The only way in which a system can do work on the surroundings is by expansion against the external pressure.

Accepted Answer

A) True 
 B)False

Question 12

The highly exothermic thermite reaction, in which aluminum reduces iron(III)  oxide to elemental iron, has been used by railroad repair crews to weld rails together.  What mass of iron is formed when 725 kJ of heat are released?

Accepted Answer

A)   47 g
B)   65 g
C)   95 g
D)   112 g
E)   130 gF) D) and E)
G) B) and E)

Question 13

Use Hess's Law to calculate the enthalpy change for the reaction  WO3(s) +3H2(g) →W(s) +3H2O(g) \mathrm{WO}_{3}(s) +3 \mathrm{H}_{2}(g)  ightarrow W(s) +3 \mathrm{H}_{2} \mathrm{O}(g) WO3​(s) +3H2​(g) →W(s) +3H2​O(g)  
from the following data:
 2 W( s) +3O2(g) →2WO3( s) ,ΔH=−1685.4 kJ2H2(g) +O2(g) →2H2O(g) ,ΔH=−477.84 kJ\begin{array}{l}2 \mathrm{~W}(\mathrm{~s}) +3 \mathrm{O}_{2}(g)  ightarrow 2 \mathrm{WO}_{3}(\mathrm{~s}) , \Delta \mathrm{H}=-1685.4 \mathrm{~kJ} \2 \mathrm{H}_{2}(g) +\mathrm{O}_{2}(g)  ightarrow 2 \mathrm{H}_{2} \mathrm{O}(g) , \Delta H=-477.84 \mathrm{~kJ}\end{array}2 W( s) +3O2​(g) →2WO3​( s) ,ΔH=−1685.4 kJ2H2​(g) +O2​(g) →2H2​O(g) ,ΔH=−477.84 kJ​

Accepted Answer

A)   125.9 kJ
B)   252.9 kJ
C)   364.9 kJ
D)   1207.6 kJ
E)   None of these choices is correct. F) None of the above
G) All of the above

Question 14

Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is:  What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

Accepted Answer

A)   -18 kJ
B)   -69 kJ
C)   -73 kJ
D)   -260 kJ
E)   None of these choices is correct.F) B) and D)
G) B) and E)

Question 15

Which one of the following is not a correct formation reaction? (products are correct)

Accepted Answer

A)    H2(g) +O(g) →H2O(g)  \mathrm{H}_{2}(g) +\mathrm{O}(g)  \rightarrow \mathrm{H}_{2} \mathrm{O}(\mathrm{g})  H2​(g) +O(g) →H2​O(g)  
B)    1/2H2(g) +1/2Cl2(g) →HCl(g)  1 / 2 \mathrm{H}_{2}(g) +1 / 2 \mathrm{Cl}_{2}(g)  \rightarrow \mathrm{HCl}(g)  1/2H2​(g) +1/2Cl2​(g) →HCl(g)  
C)    6C 6 \mathrm{C} 6C  (graphite)   +3H2(g) →C6H6(l)  +3 \mathrm{H}_{2}(g)  \rightarrow \mathrm{C}_{6} \mathrm{H}_{6}(l)  +3H2​(g) →C6​H6​(l)  
D)    C C C  (graphite  ) →C( )  \rightarrow C( ) →C(  diamond) 
E)    6C( 6 \mathrm{C}( 6C( graphite ) +6H2(g) +3O2(g) →C6H12O6( s)  ) +6 \mathrm{H}_{2}(g) +3 \mathrm{O}_{2}(g)  \rightarrow \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(\mathrm{~s})  ) +6H2​(g) +3O2​(g) →C6​H12​O6​( s) F) A) and C)
G) A) and D)

Question 16

The compound carbon suboxide, C3O2, is a gas at room temperature. Use the data supplied to calculate the heat of formation of carbon suboxide. (Data: 3O2, is a gas at room temperature. Use the data supplied to calculate the heat of formation of carbon suboxide. (Data:   \Delta H \degree  = 127.3 kJ/mol and  \Delta H \degree f of CO(g)  = -110.5 kJ/mol)  A)  116.8 B)  -93.7 C)  227.8 D)  -348.3 E)  93.7 " class="answers-bank-image d-inline" rel="preload" > Δ\DeltaΔ H °\degree°  = 127.3 kJ/mol and  Δ\DeltaΔ H °\degree° f of CO(g)  = -110.5 kJ/mol)

Accepted Answer

A)   116.8
B)   -93.7
C)   227.8
D)   -348.3
E)   93.7 F) A) and B)
G) C) and E)

Question 17

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H2O(l)   →\rightarrow→  H2O(g)   Δ\DeltaΔ H = 44.01 kJ/mol.)

Accepted Answer

A)   315 g water vapor was produced.
B)   17.5 g of water vapor was produced.
C)   17.5 mol of water vapor was produced.
D)   17.5 mol of liquid water was produced.
E)   17.5 g of liquid water was produced. F) None of the above
G) B) and C)

Question 18

Different chemical bonds have different potential energies.

Accepted Answer

A) True 
 B)False

Question 19

Which one of the following is a correct formation reaction?

Accepted Answer

A)   C(diamond)   →\rightarrow→ C(graphite) 
B)   H2(g)  + O(g)   →\rightarrow→  H2O(l) 
C)   C(graphite)  + 4H(g)   →\rightarrow→ CH4(g) 
D)   6C(graphite)  + 6H2O(s)   →\rightarrow→ C6H12O6(s) 
E)   2C(graphite)  + 3H2(g)  + ½O2(g)   →\rightarrow→ C2H5OH(l)  F) C) and E)
G) A) and D)

Exam 6: Thermochemistry: Energy Flow and Chemical Change

Correct Answer
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The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together. What mass of iron is formed when 725 kJ of heat are released?

Correct Answer
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In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Correct Answer
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Which one of the following relationships is always correct?

Correct Answer
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Correct Answer
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Different chemical bonds have different potential energies.

Correct Answer
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Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Correct Answer
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Correct Answer
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In a reaction with high energy reactants and low energy products, q is negative.

Correct Answer
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Correct Answer
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Correct Answer
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A system that does no work but which transfers heat to the surroundings has:

Correct Answer
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Which one of the following is a correct formation reaction?

Correct Answer
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In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H₂O(l) $\rightarrow$ H₂O(g) $\Delta$ H = 44.01 kJ/mol.)

Correct Answer
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Which one of the following is not a correct formation reaction? (products are correct)

Correct Answer
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Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is: What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

Correct Answer
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The only way in which a system can do work on the surroundings is by expansion against the external pressure.

Correct Answer
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Exam 6: Thermochemistry: Energy Flow and Chemical Change

Correct AnswerverifiedShow Answer

The highly exothermic thermite reaction, in which aluminum reduces iron(III) oxide to elemental iron, has been used by railroad repair crews to weld rails together. What mass of iron is formed when 725 kJ of heat are released?

Correct AnswerverifiedShow Answer

In an endothermic reaction, in going from the reactants to the products at the same temperature, the value of q is negative.

Correct AnswerverifiedShow Answer

Which one of the following relationships is always correct?

Correct AnswerverifiedShow Answer

Use the following data to calculate the standard heat (enthalpy) of formation, Δ\DeltaΔ Hf, of manganese(IV) oxide, MnO2 (s) .

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Different chemical bonds have different potential energies.

Correct AnswerverifiedShow Answer

Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

In a reaction with high energy reactants and low energy products, q is negative.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The compound carbon suboxide, C3O2, is a gas at room temperature. Use the data supplied to calculate the heat of formation of carbon suboxide. (Data: Δ\DeltaΔ H °\degree° = 127.3 kJ/mol and Δ\DeltaΔ H °\degree° f of CO(g) = -110.5 kJ/mol)

Correct AnswerverifiedShow Answer

A system that does no work but which transfers heat to the surroundings has:

Correct AnswerverifiedShow Answer

Which one of the following is a correct formation reaction?

Correct AnswerverifiedShow Answer

In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H2O(l) →\rightarrow→ H2O(g) Δ\DeltaΔ H = 44.01 kJ/mol.)

Correct AnswerverifiedShow Answer

Calculate the Δ\DeltaΔ H °\degree° rxn for the following reaction. ( Δ\DeltaΔ H °\degree° f [AsH3(g) ] = 66.4 kJ/mol; Δ\DeltaΔ H °\degree° f [H3AsO4(aq) ] = -904.6 kJ/mol; Δ\DeltaΔ H °\degree° f [H2O(l) ] = -285.8 kJ/mol)

Correct AnswerverifiedShow Answer

Which one of the following is not a correct formation reaction? (products are correct)

Correct AnswerverifiedShow Answer

Calcium hydroxide, which reacts with carbon dioxide to form calcium carbonate, was used by the ancient Romans as mortar in stone structures. The reaction for this process is: What is the enthalpy change if 3.8 mol of calcium carbonate is formed?

Correct AnswerverifiedShow Answer

The only way in which a system can do work on the surroundings is by expansion against the external pressure.

Correct AnswerverifiedShow Answer

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In a phase change of water between the liquid and the gas phases, 770.1 kJ of energy was released by the system. What was the product, and how much of it was formed in the phase change? (Data: H₂O(l) $\rightarrow$ H₂O(g) $\Delta$ H = 44.01 kJ/mol.)

Correct Answer
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