Question 1

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  False

Question 2

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: 2CO(g)  + C(s)  → C3O2(g)  ΔH° = 127.3 kJ/mol
And: ΔHf° of CO(g)  = -110.5 kJ/mol)

Accepted Answer

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

Question 3

If, as a pioneer, you wished to warm your room by taking an object heated on top of a pot-bellied stove to it, which of the following 15-pound objects, each heated to 100°C, would be the best choice? The specific heat capacity (in J/(g·K) )  for each substance is given in parentheses. Iron (0.450) , copper (0.387) , granite (0.79) , gold (0.129) , water (4.18) .

Accepted Answer

A)   iron
B)   copper
C)   granite
D)   gold
E)   waterF) All of the above
G) B) and E) E

Question 4

A Snickers® candy bar contains 280 Calories, of which the fat content accounts for 120 Calories. What is the energy of the fat content, in kJ?

Accepted Answer

A)   5.0 × 10-1 kJ
B)   29 kJ
C)   5.0 × 102 kJ
D)   1.2 × 103 kJ
E)   5.0 × 105 kJF) A) and B)
G) All of the above

Question 5

A backpacker collects snow at 0°C, and places it in a cooking pot on a camp stove. It takes 643 kJ of heat energy to melt the snow and bring the water to boiling. Assuming no heat loss, and neglecting the specific heat capacity of the pot, calculate the mass of snow that the backpacker collected. (Data: specific heat capacity of liquid water, c = 4.18 J/g·K; and: H2O(s)  → H2O(l)  ΔH = ΔHfusion = 6.02 kJ/mol)

Accepted Answer

A)   1.92 kg
B)   1.90 kg
C)   1.52 kg
D)   855 g
E)   < 800 gF) None of the above
G) B) and C)

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

Your favorite candy bar, Gummy Beakers, contains 1.2 × 106 J of energy while your favorite soft drink, Bolt, contains 6.7 × 105 J. If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?

Accepted Answer

A)   53%
B)   47%
C)   27%
D)   11%
E)   0%F) B) and E)
G) A) and E)

Question 8

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide. 4NH3(g)  + 5O2(g)  → 4NO(g)  + 6H2O(g) 
Calculate ΔH°rxn for this reaction.
ΔH°f [NH3(g) ] = -45.9 kJ/mol; ΔH°f [NO(g) ] = 90.3 kJ/mol; ΔH°f [H2O(g) ] = -241.8 kJ/mol

Accepted Answer

A)   -906.0 kJ
B)   -197.4 kJ
C)   -105.6 kJ
D)   197.4 kJ
E)   906.0 kJF) D) and E)
G) C) and E) A

Question 9

Calculate the ΔH°rxn for the following reaction. (ΔH°f [AsH3(g) ] = 66.4 kJ/mol; ΔH°f [H3AsO4(aq) ] = -904.6 kJ/mol; ΔH°f [H2O(l) ] = -285.8 kJ/mol)  H3AsO4(aq)  + 4H2(g)  → AsH3(g)  + 4H2O(l)

Accepted Answer

A)   -1981.4 kJ
B)   -685.2 kJ
C)   -172.2 kJ
D)   172.2 kJ
E)   685.2 kJF) B) and E)
G) D) and E)

Question 10

A system that undergoes an adiabatic change and does work on the surroundings has

Accepted Answer

A) w B) w > 0, ΔE > 0. C) w > 0, ΔE D) w 0. E) w < 0, ΔE < 0.F) A) and C) G) A) and B)

Question 11

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w)  done by the system, in J, is

Accepted Answer

A)   1.00 J.
B)   2.00 J.
C)   1.01 × 102 J.
D)   1.01 × 105 J.
E)   None of these choices are correct.F) A) and B)
G) A) and C)

Question 12

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

Accepted Answer

A)   H2(g)  + O(g)  → H2O(l) 
B)   ½H2(g)  + ½Cl2(g)  → HCl(g) 
C)   6C(graphite)  + 3H2(g)  →C6H6(l) 
D)   C(graphite)  → C(diamond) 
E)   6C(graphite)  + 6H2(g)  + 3O2(g)  → C6H12O6(s) F) B) and E)
G) C) and D)

Question 13

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Accepted Answer

A)   32.7 kJ
B)   46.5 kJ
C)   75.9 kJ
D)   82.8 kJ
E)   89.7 kJF) A) and D)
G) B) and E)

Question 14

Combustion of a hydrocarbon will release more energy than combustion of an equal mass of carbohydrate because

Accepted Answer

A)   the C-O and O-H single bonds in carbohydrates are weak.
B)   carbohydrates contain C-O and O-H bonds and hydrocarbons do not.
C)   the total energy of the C-C and C-H bonds in hydrocarbons is greater than the total energy of the C=O and O-H bonds in the combustion products (carbon dioxide and water) .
D)   the total energy of the bonds in hydrocarbons is greater than the energy of the bonds in carbohydrates.
E)   hydrocarbons have higher molar masses than carbohydrates.F) A) and B)
G) A) and C)

Question 15

Standard heats (enthalpies) of formation of compounds, ΔH°f, may be positive or negative.

Accepted Answer

A) True 
 B)False

Question 16

Ethylene glycol, used as a coolant in automotive engines, has a specific heat capacity of 2.42 J/(g·K) . Calculate q when 3.65 kg of ethylene glycol is cooled from 132°C to 85°C.

Accepted Answer

A)   -1900 kJ
B)   -420 kJ
C)   -99 kJ
D)   -0.42 kJ
E)   -4.2 × 10-6 kJF) B) and E)
G) A) and C)

Question 17

Which of the following is not a state function?

Accepted Answer

A)   internal energy
B)   volume
C)   work
D)   pressure
E)   enthalpyF) A) and E)
G) B) and D)

Question 18

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)  → H2O(g)  ΔH = 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) All of the above
G) C) and D)

Question 19

Which one of the following is a correct formation reaction?

Accepted Answer

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

Question 20

Calculate the enthalpy change for the reaction NO(g)  + O(g)  → NO2(g) 
From the following data:
NO(g)  + O3(g)  → NO2(g)  + O2(g)  ΔH = -198.9 kJ
O3(g)  → 1.5O2(g)  ΔH = -142.3 kJ
O2(g)  → 2O(g)  ΔH = 495.0 kJ

Accepted Answer

A)   -551.6 kJ
B)   -304.1 kJ
C)   190.9 kJ
D)   153.8 kJ
E)   438.4 kJF) B) and C)
G) A) and E)

Exam 6: Thermochemistry Energy Flow and Chemical Change

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

Correct Answer
verified
False

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: 2CO(g) + C(s) → C₃O₂(g) ΔH° = 127.3 kJ/mol And: ΔH_f° of CO(g) = -110.5 kJ/mol)

Correct Answer
verified

Correct Answer
verified
E

A Snickers^® candy bar contains 280 Calories, of which the fat content accounts for 120 Calories. What is the energy of the fat content, in kJ?

Correct Answer
verified

Correct Answer
verified

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

Correct Answer
verified

Your favorite candy bar, Gummy Beakers, contains 1.2 × 10⁶ J of energy while your favorite soft drink, Bolt, contains 6.7 × 10⁵ J. If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?

Correct Answer
verified

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide. 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) Calculate ΔH°_rxn for this reaction. ΔH°_f[NH₃(g) ] = -45.9 kJ/mol; ΔH°_f [NO(g) ] = 90.3 kJ/mol; ΔH°_f [H₂O(g) ] = -241.8 kJ/mol

Correct Answer
verified
A

Calculate the ΔH°_rxn for the following reaction. (ΔH°_f[AsH₃(g) ] = 66.4 kJ/mol; ΔH°_f[H₃AsO₄(aq) ] = -904.6 kJ/mol; ΔH°_f[H₂O(l) ] = -285.8 kJ/mol) H₃AsO₄(aq) + 4H₂(g) → AsH₃(g) + 4H₂O(l)

Correct Answer
verified

A system that undergoes an adiabatic change and does work on the surroundings has

Correct Answer
verified

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system, in J, is

Correct Answer
verified

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

Correct Answer
verified

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Correct Answer
verified

Combustion of a hydrocarbon will release more energy than combustion of an equal mass of carbohydrate because

Correct Answer
verified

Standard heats (enthalpies) of formation of compounds, ΔH°_f, may be positive or negative.

Correct Answer
verified

Ethylene glycol, used as a coolant in automotive engines, has a specific heat capacity of 2.42 J/(g·K) . Calculate q when 3.65 kg of ethylene glycol is cooled from 132°C to 85°C.

Correct Answer
verified

Which of the following is not a state function?

Correct Answer
verified

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) → H₂O(g) ΔH = 44.01 kJ/mol.)

Correct Answer
verified

Which one of the following is a correct formation reaction?

Correct Answer
verified

Calculate the enthalpy change for the reaction NO(g) + O(g) → NO₂(g) From the following data: NO(g) + O₃(g) → NO₂(g) + O₂(g) ΔH = -198.9 kJ O₃(g) → 1.5O₂(g) ΔH = -142.3 kJ O₂(g) → 2O(g) ΔH = 495.0 kJ

Correct Answer
verified

Exam 6: Thermochemistry Energy Flow and Chemical Change

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

Correct AnswerverifiedFalse

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: 2CO(g) + C(s) → C3O2(g) ΔH° = 127.3 kJ/mol And: ΔHf° of CO(g) = -110.5 kJ/mol)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedE

A Snickers® candy bar contains 280 Calories, of which the fat content accounts for 120 Calories. What is the energy of the fat content, in kJ?

Correct AnswerverifiedShow Answer

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

Your favorite candy bar, Gummy Beakers, contains 1.2 × 106 J of energy while your favorite soft drink, Bolt, contains 6.7 × 105 J. If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?

Correct AnswerverifiedShow Answer

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide. 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) Calculate ΔH°rxn for this reaction. ΔH°f [NH3(g) ] = -45.9 kJ/mol; ΔH°f [NO(g) ] = 90.3 kJ/mol; ΔH°f [H2O(g) ] = -241.8 kJ/mol

Correct AnswerverifiedA

Calculate the ΔH°rxn for the following reaction. (ΔH°f [AsH3(g) ] = 66.4 kJ/mol; ΔH°f [H3AsO4(aq) ] = -904.6 kJ/mol; ΔH°f [H2O(l) ] = -285.8 kJ/mol) H3AsO4(aq) + 4H2(g) → AsH3(g) + 4H2O(l)

Correct AnswerverifiedShow Answer

A system that undergoes an adiabatic change and does work on the surroundings has

Correct AnswerverifiedShow Answer

A system expands from a volume of 1.00 L to 2.00 L against a constant external pressure of 1.00 atm. The work (w) done by the system, in J, is

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

A system absorbs 21.6 kJ of heat while performing 6.9 kJ of work on the surroundings. If the initial internal energy, E, is 61.2 kJ, what is the final value of E?

Correct AnswerverifiedShow Answer

Combustion of a hydrocarbon will release more energy than combustion of an equal mass of carbohydrate because

Correct AnswerverifiedShow Answer

Standard heats (enthalpies) of formation of compounds, ΔH°f, may be positive or negative.

Correct AnswerverifiedShow Answer

Ethylene glycol, used as a coolant in automotive engines, has a specific heat capacity of 2.42 J/(g·K) . Calculate q when 3.65 kg of ethylene glycol is cooled from 132°C to 85°C.

Correct AnswerverifiedShow Answer

Which of the following is not a state function?

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) → H2O(g) ΔH = 44.01 kJ/mol.)

Correct AnswerverifiedShow Answer

Which one of the following is a correct formation reaction?

Correct AnswerverifiedShow Answer

Calculate the enthalpy change for the reaction NO(g) + O(g) → NO2(g) From the following data: NO(g) + O3(g) → NO2(g) + O2(g) ΔH = -198.9 kJ O3(g) → 1.5O2(g) ΔH = -142.3 kJ O2(g) → 2O(g) ΔH = 495.0 kJ

Correct AnswerverifiedShow Answer

Correct Answer
verified
False

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: 2CO(g) + C(s) → C₃O₂(g) ΔH° = 127.3 kJ/mol And: ΔH_f° of CO(g) = -110.5 kJ/mol)

Correct Answer
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Correct Answer
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E

A Snickers^® candy bar contains 280 Calories, of which the fat content accounts for 120 Calories. What is the energy of the fat content, in kJ?

Correct Answer
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Correct Answer
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Correct Answer
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Your favorite candy bar, Gummy Beakers, contains 1.2 × 10⁶ J of energy while your favorite soft drink, Bolt, contains 6.7 × 10⁵ J. If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?

Correct Answer
verified

An important step in the synthesis of nitric acid is the conversion of ammonia to nitric oxide. 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) Calculate ΔH°_rxn for this reaction. ΔH°_f[NH₃(g) ] = -45.9 kJ/mol; ΔH°_f [NO(g) ] = 90.3 kJ/mol; ΔH°_f [H₂O(g) ] = -241.8 kJ/mol

Correct Answer
verified
A

Calculate the ΔH°_rxn for the following reaction. (ΔH°_f[AsH₃(g) ] = 66.4 kJ/mol; ΔH°_f[H₃AsO₄(aq) ] = -904.6 kJ/mol; ΔH°_f[H₂O(l) ] = -285.8 kJ/mol) H₃AsO₄(aq) + 4H₂(g) → AsH₃(g) + 4H₂O(l)

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Standard heats (enthalpies) of formation of compounds, ΔH°_f, may be positive or negative.

Correct Answer
verified

Correct Answer
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Correct Answer
verified

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) → H₂O(g) ΔH = 44.01 kJ/mol.)

Correct Answer
verified

Correct Answer
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Calculate the enthalpy change for the reaction NO(g) + O(g) → NO₂(g) From the following data: NO(g) + O₃(g) → NO₂(g) + O₂(g) ΔH = -198.9 kJ O₃(g) → 1.5O₂(g) ΔH = -142.3 kJ O₂(g) → 2O(g) ΔH = 495.0 kJ

Correct Answer
verified