Question 1

The Starship Enterprise is caught in a time warp and Spock is forced to use the primitive techniques of the 20th century to determine the specific heat capacity of an unknown mineral. The 307-g sample was heated to 98.7°C and placed into a calorimeter containing 72.4 g of water at 23.6°C. The heat capacity of the calorimeter was 15.7 J/K. The final temperature in the calorimeter was 32.4°C. What is the specific heat capacity of the mineral?

Accepted Answer

A)   0.124 J/(g·K) 
B)   0.131 J/(g·K) 
C)   0.138 J/(g·K) 
D)   0.145 J/(g·K) 
E)   none of the above

Question 2

Nitric acid, which is among the top 15 chemicals produced in the United States, was first prepared over 1200 years ago by heating naturally occurring sodium nitrate (called saltpeter)  with sulfuric acid and collecting the vapors produced. Calculate H°rxn for this reaction. H°f [NaNO3(s) ] = -467.8 kJ/mol; H°f [NaHSO4(s) ] = -1125.5 kJ/mol; H°f [H2SO4(l)  = -814.0 kJ/mol; H°f [HNO3(g) ] = -135.1 kJ/mol
NaNO3(s)  + H2SO4(l)   NaHSO4(s)  + HNO3(g)

Accepted Answer

A)   -644.2 kJ
B)   -291.4 kJ
C)   -21.2 kJ
D)   21.2 kJ
E)   644.2 kJ

Question 3

F1F1F1S1F1F1F10E values obtained by bomb calorimetry can be converted to give accurate F1F1F1S1F1F1F10H values.

Accepted Answer

A) True 
 B)False

Question 4

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

Accepted Answer

A)   w E = 0.
B)   w > 0, E > 0.
C)   w > 0, E 
D)   w E > 0.
E)   w E < 0.

Question 5

In which of the following processes is H = E ?

Accepted Answer

A)   Two moles of ammonia gas are cooled from 325°C to 300°C at 1.2 atm.
B)   One gram of water is vaporized at 100°C and 1 atm.
C)   Two moles of hydrogen iodide gas react to form hydrogen gas and iodine gas in a 40-L container.
D)   Calcium carbonate is heated to form calcium oxide and carbon dioxide in a container with variable volume.
E)   One mole of solid carbon dioxide sublimes to the gas phase.

Question 6

When 1.00 g of solid NH4Cl is dissolved in 25.00 g of water contained in a coffee cup calorimeter, both reagents initially being at 25.0°C, the temperature falls to 22.4°C. Assuming that the heat capacity of the ammonium chloride solution is 4.18 J/(g·K), calculate the heat (enthalpy) of solution of NH4Cl, (a) in J/g and (b) in kJ/mol.

Accepted Answer

Question 7

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)  H° = 127.3 kJ/mol
And: Hf° of CO(g)  = -110.5 kJ/mol)

Accepted Answer

A)   116.8
B)   -93.7
C)   227.8
D)   -348.3
E)   93.7

Question 8

A mass of 1.250 g of benzoic acid (C7H6O2) was completely combusted in a bomb calorimeter. If the heat capacity of the calorimeter was 10.134 kJ/K and the heat of combustion of benzoic acid is -3226 kJ/mol, calculate (to three decimal places) the temperature increase that should have occurred in the apparatus.

Accepted Answer

Temperatur...

Question 9

Use the following data to calculate the standard heat (enthalpy)  of formation, H°f , of manganese(IV)  oxide, MnO2 (s) . 
2MnO2(s)   2MnO(s)  + O2(g)  H = 264 kJ
MnO2(s)  + Mn(s)   2MnO(s)  H = -240 kJ

Accepted Answer

A)   -504 kJ
B)   -372 kJ
C)   -24 kJ
D)   24 kJ
E)   504 kJ

Question 10

The specific heat capacity c of a metal is approximately related to its molar mass K. Use this relationship to identify the metal which has a specific heat capacity of 0.900 J/gK. A)  Li B)  Sn C)  Ca D)  Al E)  U" class="answers-bank-image d-inline" rel="preload" > as follows: c × K. Use this relationship to identify the metal which has a specific heat capacity of 0.900 J/gK. A)  Li B)  Sn C)  Ca D)  Al E)  U" class="answers-bank-image d-inline" rel="preload" > = 3R, where R is the universal gas constant, 8.314 J/molK. Use this relationship to identify the metal which has a specific heat capacity of 0.900 J/gK.

Accepted Answer

A)   Li
B)   Sn
C)   Ca
D)   Al
E)   U

Question 11

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)  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.

Question 12

Which one of the following relationships is always correct?

Accepted Answer

A)   potential energy + kinetic energy = constant
B)   E = q + w
C)   .E = H - PV
D)   H = E + PV
E)   .H = qv

Question 13

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 the above.

Question 14

a. Starting from the equation H = E + PV, show how the relationship F1F1F1S1F1F1F10H = qp is derived. Clearly indicate any necessary assumptions or conditions.
b. In one sentence, state in full what is meant by the equation: F1F1F1S1F1F1F10H = qp.

Accepted Answer

a. Since H = E + PV (defining equation f...

Question 15

Diborane (B2H6) has been considered as a possible rocket fuel. Calculate F1F1F1S1F1F1F10H° for the reaction
B2H6(g) F1F1F1S1F1F1F10 2B(s) + 3H2(g)
using the following data:   O2(g) F1F1F1S1F1F1F10 H2O(g)
-242

Accepted Answer

<font face="symbol">F...

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 kJ

Question 17

F1F1F1S1F1F1F10H does not depend on the path of a reaction, but F1F1F1S1F1F1F10E does.

Accepted Answer

A) True 
 B)False

Question 18

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

Question 19

a. A gas sample absorbs 53 kJ of heat and does 18 kJ of work. Calculate the change in its internal energy.
b. A system expands against a constant pressure of 1.50 atm, from an initial volume of 1.00 L to a final volume of 10.0 L. Calculate the work (w) involved in this process, in kJ.

Accepted Answer

a. F1F1F1S...

Question 20

Starting from equations relating pressure to force and force to work, derive the relationship w = - PF1F1F1S1F1F1F10V, explaining the steps in your argument.

Accepted Answer

Consider the system being contained in a...

Exam 6: Thermochemistry: Energy Flow and Chemical Change

In which of the following processes is H = E ?

Correct Answer
verified

H does not depend on the path of a reaction, but E does.

Correct Answer
verified

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

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

Correct Answer
verified
Temperatur...
View Answer

Correct Answer
verified

Correct Answer
verified

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) H° = 127.3 kJ/mol And: H_f^° of CO(g) = -110.5 kJ/mol)

Correct Answer
verified

a. Starting from the equation H = E + PV, show how the relationship H = q_p is derived. Clearly indicate any necessary assumptions or conditions. b. In one sentence, state in full what is meant by the equation: H = q_p.

Correct Answer
verified
a. Since H = E + PV (defining equation f...
View Answer

E values obtained by bomb calorimetry can be converted to give accurate H values.

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) H = 44.01 kJ/mol.)

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

Use the following data to calculate the standard heat (enthalpy) of formation, H°_f , of manganese(IV) oxide, MnO₂(s) . 2MnO₂(s)  2MnO(s) + O₂(g) H = 264 kJ MnO₂(s) + Mn(s)  2MnO(s) H = -240 kJ

Correct Answer
verified

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

Correct Answer
verified

a. A gas sample absorbs 53 kJ of heat and does 18 kJ of work. Calculate the change in its internal energy. b. A system expands against a constant pressure of 1.50 atm, from an initial volume of 1.00 L to a final volume of 10.0 L. Calculate the work (w) involved in this process, in kJ.

Correct Answer
verified
a. F1F1F1S...
View Answer

Diborane (B₂H₆) has been considered as a possible rocket fuel. Calculate H° for the reaction B₂H₆(g)  2B(s) + 3H₂(g) using the following data: O₂(g)  H₂O(g) -242

Correct Answer
verified
F...
View Answer

Correct Answer
verified

The specific heat capacity c of a metal is approximately related to its molar mass as follows: c × = 3R, where R is the universal gas constant, 8.314 J/molK. Use this relationship to identify the metal which has a specific heat capacity of 0.900 J/gK.

Correct Answer
verified

Starting from equations relating pressure to force and force to work, derive the relationship w = - PV, explaining the steps in your argument.

Correct Answer
verified
Consider the system being contained in a...
View Answer

Which one of the following relationships is always correct?

Correct Answer
verified

Exam 6: Thermochemistry: Energy Flow and Chemical Change

In which of the following processes is H = E ?

Correct AnswerverifiedShow Answer

H does not depend on the path of a reaction, but E does.

Correct AnswerverifiedShow Answer

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

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

Correct AnswerverifiedTemperatur...View AnswerShow Answer

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: 2CO(g) + C(s)  C3O2(g) H° = 127.3 kJ/mol And: Hf° of CO(g) = -110.5 kJ/mol)

Correct AnswerverifiedShow Answer

a. Starting from the equation H = E + PV, show how the relationship H = qp is derived. Clearly indicate any necessary assumptions or conditions. b. In one sentence, state in full what is meant by the equation: H = qp.

Correct Answerverifieda. Since H = E + PV (defining equation f...View AnswerShow Answer

E values obtained by bomb calorimetry can be converted to give accurate H values.

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) H = 44.01 kJ/mol.)

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

Use the following data to calculate the standard heat (enthalpy) of formation, H°f , of manganese(IV) oxide, MnO2 (s) . 2MnO2(s)  2MnO(s) + O2(g) H = 264 kJ MnO2(s) + Mn(s)  2MnO(s) H = -240 kJ

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

a. A gas sample absorbs 53 kJ of heat and does 18 kJ of work. Calculate the change in its internal energy. b. A system expands against a constant pressure of 1.50 atm, from an initial volume of 1.00 L to a final volume of 10.0 L. Calculate the work (w) involved in this process, in kJ.

Correct Answerverifieda. F1F1F1S...View AnswerShow Answer

Diborane (B2H6) has been considered as a possible rocket fuel. Calculate H° for the reaction B2H6(g)  2B(s) + 3H2(g) using the following data: O2(g)  H2O(g) -242

Correct AnswerverifiedF...View AnswerShow Answer

Correct AnswerverifiedShow Answer

The specific heat capacity c of a metal is approximately related to its molar mass as follows: c × = 3R, where R is the universal gas constant, 8.314 J/molK. Use this relationship to identify the metal which has a specific heat capacity of 0.900 J/gK.

Correct AnswerverifiedShow Answer

Starting from equations relating pressure to force and force to work, derive the relationship w = - PV, explaining the steps in your argument.

Correct AnswerverifiedConsider the system being contained in a...View AnswerShow Answer

Which one of the following relationships is always correct?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Temperatur...
View Answer

Correct Answer
verified

Correct Answer
verified

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) H° = 127.3 kJ/mol And: H_f^° of CO(g) = -110.5 kJ/mol)

Correct Answer
verified

a. Starting from the equation H = E + PV, show how the relationship H = q_p is derived. Clearly indicate any necessary assumptions or conditions. b. In one sentence, state in full what is meant by the equation: H = q_p.

Correct Answer
verified
a. Since H = E + PV (defining equation f...
View Answer

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) H = 44.01 kJ/mol.)

Correct Answer
verified

Correct Answer
verified

Use the following data to calculate the standard heat (enthalpy) of formation, H°_f , of manganese(IV) oxide, MnO₂(s) . 2MnO₂(s)  2MnO(s) + O₂(g) H = 264 kJ MnO₂(s) + Mn(s)  2MnO(s) H = -240 kJ

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified
a. F1F1F1S...
View Answer

Diborane (B₂H₆) has been considered as a possible rocket fuel. Calculate H° for the reaction B₂H₆(g)  2B(s) + 3H₂(g) using the following data: O₂(g)  H₂O(g) -242

Correct Answer
verified
F...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Consider the system being contained in a...
View Answer

Correct Answer
verified