Question 1

For a system at constant pressure,19,400 calories of heat are released.This quantity of heat is equivalent to

Accepted Answer

A) 6.92 × 10-5 J. 
B) 8.12 × 103 J. 
C) 1.94 × 104 J. 
D) 8.12 × 104 J. 
A) 6.92 × 10-5 J. 
B) 8.12 × 103 J. 
C) 1.94 × 104 J. 
D) 8.12 × 104 J.

Question 2

Most chemical reactions are carried out in one of two ways: I.in an open vessel at constant atmospheric pressure
II.in a closed vessel
Which is true?

Accepted Answer

A) ΔH = q for condition I and ΔE = q for condition II. 
B) ΔE = q for condition I and ΔH = q for condition II. 
C) ΔH = w for condition I and ΔE = w for condition II. 
D) ΔE = w for condition I and ΔH = w for condition II. 
A) ΔH = q for condition I and ΔE = q for condition II. 
B) ΔE = q for condition I and ΔH = q for condition II. 
C) ΔH = w for condition I and ΔE = w for condition II. 
D) ΔE = w for condition I and ΔH = w for condition II.

Question 3

Calculate ΔG° for the reaction below and tell whether it is spontaneous or nonspontaneous under standard conditions at 25°C. 2 S (s)+ 3 O2 (g)+ 2 H2O (l)→ 2 H2SO4 (l)ΔH° = -1056 kJ/mol
ΔS° = -505 J/mol

Accepted Answer

A) ΔG° = -1207 kJ and the process is spontaneous. 
B) ΔG° = -1207 kJ and the process is nonspontaneous. 
C) ΔG° = -906 kJ and the process is spontaneous. 
D) ΔG° = -906 kJ and the process is nonspontaneous. 
A) ΔG° = -1207 kJ and the process is spontaneous. 
B) ΔG° = -1207 kJ and the process is nonspontaneous. 
C) ΔG° = -906 kJ and the process is spontaneous. 
D) ΔG° = -906 kJ and the process is nonspontaneous.

Question 4

Ethyl alcohol is produced by the fermentation of glucose,C6H12O6. C6H12O6(s)→ 2 C2H5OH(l)+ 2 CO2(g)ΔH° = -69.1 kJ
Given that the enthalpy of formation is -277.7 kJ/mol for C2H5OH(l)and -393.5 kJ/mol for CO2(g),find the enthalpy of formation for C6H12O6.

Accepted Answer

A) -1411.5 kJ/mol 
B) -1273.3 kJ/mol 
C) -740.3 kJ/mol 
D) -602.1 kJ/mol 
A) -1411.5 kJ/mol 
B) -1273.3 kJ/mol 
C) -740.3 kJ/mol 
D) -602.1 kJ/mol

Question 5

What are the signs of ΔH,ΔS,and ΔG for the following spontaneous change?

Accepted Answer

A) ΔH = +,ΔS = +,ΔG = - 
B) ΔH = +,ΔS = -,ΔG = - 
C) ΔH = -,ΔS = +,ΔG = - 
D) ΔH = -,ΔS = -,ΔG = - 
A) ΔH = +,ΔS = +,ΔG = - 
B) ΔH = +,ΔS = -,ΔG = - 
C) ΔH = -,ΔS = +,ΔG = - 
D) ΔH = -,ΔS = -,ΔG = -

Question 6

A process is carried out at constant pressure.Given that ΔE is positive and ΔH is negative,

Accepted Answer

A) the system absorbs heat and expands during the process. 
B) the system absorbs heat and contracts during the process. 
C) the system loses heat and expands during the process. 
D) the system loses heat and contracts during the process. 
A) the system absorbs heat and expands during the process. 
B) the system absorbs heat and contracts during the process. 
C) the system loses heat and expands during the process. 
D) the system loses heat and contracts during the process.

Question 7

At a given temperature and pressure,which of the following would be expected to have the greatest molar entropy?

Accepted Answer

A) I2(s) 
B) I2(l) 
C) I2(g) 
D) All of these would be expected to have the same molar entropy. 
A) I2(s) 
B) I2(l) 
C) I2(g) 
D) All of these would be expected to have the same molar entropy.

Question 8

Which of the following is not a state function?

Accepted Answer

A) depth 
B) heat 
C) internal energy 
D) gas 
A) depth 
B) heat 
C) internal energy 
D) gas

Question 9

Energy can be classified as either ________ energy (energy of motion)or ________ energy (stored energy).

Accepted Answer

The answer of Energy can be classified as either ________...

Question 10

The following drawing is a representation of a reaction of the type A → B,where different shaded spheres represent different molecular structures.For this reaction ΔH° = -30 kJ.This reaction is likely to be

Accepted Answer

A) nonspontaneous at all temperatures. 
B) nonspontaneous at low temperatures and spontaneous at high temperatures. 
C) spontaneous at low temperatures and nonspontaneous at high temperatures. 
D) spontaneous at all temperatures. 
A) nonspontaneous at all temperatures. 
B) nonspontaneous at low temperatures and spontaneous at high temperatures. 
C) spontaneous at low temperatures and nonspontaneous at high temperatures. 
D) spontaneous at all temperatures.

Question 11

A reaction is performed in a water bath initially at 28°C which decreases to 10°C by the end of the reaction.For this reaction the sign of heat transfer is ________,and the reaction is classified as ________.

Accepted Answer

positive,e

Question 12

When 0.700 g of anthracene,C14H10,is combusted in a bomb calorimeter that has a water jacket containing 500.g of water,the temperature of the water increases by 13.27°C.Assuming that the specific heat of water is 4.18 J/(g ∙ °C),and that the heat absorption by the calorimeter is negligible,estimate the enthalpy of combustion per mole of anthracene.

Accepted Answer

A) +39.7 kJ/mol 
B) -39.7 kJ/mol 
C) -7060 kJ/mol 
D) -8120 kJ/mol 
A) +39.7 kJ/mol 
B) -39.7 kJ/mol 
C) -7060 kJ/mol 
D) -8120 kJ/mol

Question 13

For the expansion of an ideal gas into a vacuum at constant temperature,ΔH = 0.What can be said about ΔE and ΔS?

Accepted Answer

A) ΔE is negative and ΔS is positive. 
B) ΔE is zero and ΔS is positive. 
C) ΔE is negative and ΔS is zero. 
D) ΔE is positive and ΔS is negative. 
A) ΔE is negative and ΔS is positive. 
B) ΔE is zero and ΔS is positive. 
C) ΔE is negative and ΔS is zero. 
D) ΔE is positive and ΔS is negative.

Question 14

For which reaction is H expected to be most positive?

Accepted Answer

A) Cl2(g)→ 2 Cl(g) 
B) I2(g)→ 2 I(g) 
C) 2 Cl(g)→ Cl2(g) 
D) 2 I(g)→ I2(g) 
A) Cl2(g)→ 2 Cl(g) 
B) I2(g)→ 2 I(g) 
C) 2 Cl(g)→ Cl2(g) 
D) 2 I(g)→ I2(g)

Question 15

In the reaction below,is energy released or absorbed by the system? What is the sign of the energy change,E?
432 kJ + A + 2B → 3C

Accepted Answer

The answer of In the reaction below,is energy released or...

Question 16

Which is expected to have the largest carbon-oxygen bond dissociation energy?

Accepted Answer

A) CO 
B) CO2  
C) H2CO3 
D) HCOOH  
A) CO 
B) CO2  
C) H2CO3 
D) HCOOH

Question 17

Given: S (s)+ O2 (g)→ SO2 (g)ΔH° = -296.1 kJ 2 SO3 (g)→ 2 SO2 (g)+ O2 (g)ΔH° = 198.2 kJ
Find ΔH° for : 2 S(s)+ 3 O2(g)→ 2 SO3(g)

Accepted Answer

A) -790.4 kJ 
B) -394.0 kJ 
C) -97.9 kJ 
D) +97.9 kJ 
A) -790.4 kJ 
B) -394.0 kJ 
C) -97.9 kJ 
D) +97.9 kJ

Question 18

The specific heat of copper is 0.385 J/(g ∙ °C).If 34.2 g of copper,initially at 21.0°C,absorbs 4.689 kJ,what will be the final temperature of the copper?

Accepted Answer

A) 21.4°C 
B) 23.8°C 
C) 356°C 
D) 377°C 
A) 21.4°C 
B) 23.8°C 
C) 356°C 
D) 377°C

Question 19

When 10.0 mol of benzene is vaporized at a constant pressure of 1.00 atm and at its normal boiling point of 80.1°C,339 kJ are absorbed and PΔV for the vaporization process is equal to 29.0 kJ,then

Accepted Answer

A) ΔE = 310.kJ and ΔH = 339.kJ. 
B) ΔE = 368.kJ and ΔH = 339.kJ. 
C) ΔE = 339.kJ and ΔH = 310.kJ. 
D) ΔE = 339.kJ and ΔH = 368.kJ. 
A) ΔE = 310.kJ and ΔH = 339.kJ. 
B) ΔE = 368.kJ and ΔH = 339.kJ. 
C) ΔE = 339.kJ and ΔH = 310.kJ. 
D) ΔE = 339.kJ and ΔH = 368.kJ.

Question 20

The enthalpy of fusion,or heat of fusion (ΔHfusion),of water is positive and corresponds to which physical change?

Accepted Answer

A) H2O(g)→ H2O(s) 
B) H2O(l)→ H2O(s) 
C) H2O(s)→ H2O(l) 
D) H2O(s)→ H2O(g) 
A) H2O(g)→ H2O(s) 
B) H2O(l)→ H2O(s) 
C) H2O(s)→ H2O(l) 
D) H2O(s)→ H2O(g)

Exam 9: Thermochemistry: Chemical Energy

For a system at constant pressure,19,400 calories of heat are released.This quantity of heat is equivalent to

Most chemical reactions are carried out in one of two ways: I.in an open vessel at constant atmospheric pressure II.in a closed vessel Which is true?

Calculate ΔG° for the reaction below and tell whether it is spontaneous or nonspontaneous under standard conditions at 25°C. 2 S (s)+ 3 O2 (g)+ 2 H2O (l)→ 2 H2SO4 (l)ΔH° = -1056 kJ/mol ΔS° = -505 J/mol

Ethyl alcohol is produced by the fermentation of glucose,C6H12O6. C6H12O6(s)→ 2 C2H5OH(l)+ 2 CO2(g)ΔH° = -69.1 kJ Given that the enthalpy of formation is -277.7 kJ/mol for C2H5OH(l)and -393.5 kJ/mol for CO2(g),find the enthalpy of formation for C6H12O6.

What are the signs of ΔH,ΔS,and ΔG for the following spontaneous change?

A process is carried out at constant pressure.Given that ΔE is positive and ΔH is negative,

At a given temperature and pressure,which of the following would be expected to have the greatest molar entropy?

Which of the following is not a state function?

Energy can be classified as either ________ energy (energy of motion)or ________ energy (stored energy).

The following drawing is a representation of a reaction of the type A → B,where different shaded spheres represent different molecular structures.For this reaction ΔH° = -30 kJ.This reaction is likely to be

A reaction is performed in a water bath initially at 28°C which decreases to 10°C by the end of the reaction.For this reaction the sign of heat transfer is ________,and the reaction is classified as ________.

For the expansion of an ideal gas into a vacuum at constant temperature,ΔH = 0.What can be said about ΔE and ΔS?

For which reaction is H expected to be most positive?

In the reaction below,is energy released or absorbed by the system? What is the sign of the energy change,E? 432 kJ + A + 2B → 3C

Which is expected to have the largest carbon-oxygen bond dissociation energy?

Given: S (s)+ O2 (g)→ SO2 (g)ΔH° = -296.1 kJ 2 SO3 (g)→ 2 SO2 (g)+ O2 (g)ΔH° = 198.2 kJ Find ΔH° for : 2 S(s)+ 3 O2(g)→ 2 SO3(g)

The specific heat of copper is 0.385 J/(g ∙ °C).If 34.2 g of copper,initially at 21.0°C,absorbs 4.689 kJ,what will be the final temperature of the copper?

When 10.0 mol of benzene is vaporized at a constant pressure of 1.00 atm and at its normal boiling point of 80.1°C,339 kJ are absorbed and PΔV for the vaporization process is equal to 29.0 kJ,then

The enthalpy of fusion,or heat of fusion (ΔHfusion),of water is positive and corresponds to which physical change?

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Calculate ΔG° for the reaction below and tell whether it is spontaneous or nonspontaneous under standard conditions at 25°C. 2 S (s)+ 3 O₂ (g)+ 2 H₂O (l)→ 2 H₂SO₄ (l)ΔH° = -1056 kJ/mol ΔS° = -505 J/mol

Ethyl alcohol is produced by the fermentation of glucose,C₆H₁₂O₆. C₆H₁₂O₆(s)→ 2 C₂H₅OH(l)+ 2 CO₂(g)ΔH° = -69.1 kJ Given that the enthalpy of formation is -277.7 kJ/mol for C₂H₅OH(l)and -393.5 kJ/mol for CO₂(g),find the enthalpy of formation for C₆H₁₂O₆.

Energy can be classified as either energy (energy of motion)or energy (stored energy).

A reaction is performed in a water bath initially at 28°C which decreases to 10°C by the end of the reaction.For this reaction the sign of heat transfer is ,and the reaction is classified as .

Given: S (s)+ O₂ (g)→ SO₂ (g)ΔH° = -296.1 kJ 2 SO₃ (g)→ 2 SO₂ (g)+ O₂ (g)ΔH° = 198.2 kJ Find ΔH° for : 2 S(s)+ 3 O₂(g)→ 2 SO₃(g)

The enthalpy of fusion,or heat of fusion (ΔH_fusion),of water is positive and corresponds to which physical change?