Question 1

Which of the following statements is true?

Accepted Answer

A)  If a reaction has $\Delta$GrS1U1P1$\circ$S1S1P0S1U1P1S1S1P0 = 275 kJ.mol-1, it must proceed rapidly toward equilibrium. 
B)  All endothermic reactions are nonspontaneous. 
C)  The value of $\Delta$GrS1U1P1$\circ$S1S1P0
 is not dependent on temperature. 
D)  A spontaneous reaction for which the entropy change is negative is entropy driven. 
E)  If a certain reaction is spontaneous, it is not spontaneous in the reverse direction. 
A)  If a reaction has $\Delta$GrS1U1P1$\circ$S1S1P0S1U1P1S1S1P0 = 275 kJ.mol-1, it must proceed rapidly toward equilibrium. 
B)  All endothermic reactions are nonspontaneous. 
C)  The value of $\Delta$GrS1U1P1$\circ$S1S1P0
 is not dependent on temperature. 
D)  A spontaneous reaction for which the entropy change is negative is entropy driven. 
E)  If a certain reaction is spontaneous, it is not spontaneous in the reverse direction. E

Question 2

Use the Boltzmann formula to calculate the entropy at T = 0 of 1.00 mol chlorobenzene, C6H5Cl,Where each molecule can be oriented in any of six ways.

Accepted Answer

A)  0 J.K-1; at T = 0, there is no randomness. 
B)  -15 J.K-1 
C)  -30 J.K-1 
D)  +30 J.K-1 
E)  +15 J.K-1 
A)  0 J.K-1; at T = 0, there is no randomness. 
B)  -15 J.K-1 
C)  -30 J.K-1 
D)  +30 J.K-1 
E)  +15 J.K-1 E

Question 3

Calculate the lattice enthalpy of potassium chloride given the following enthalpy data.
 $$\begin{array} { l l } 
\mathrm { K } ( \mathrm { s } ) \rightarrow \mathrm { K } ( \mathrm { g } ) & + 89 \mathrm {~kJ} \cdot \mathrm { mol } ^ { - 1 } \
\mathrm {~K} ( \mathrm {~g} ) \rightarrow \mathrm { K } ^ { + } ( \mathrm { g } ) + \mathrm { e } ^ { - } & + 418 \mathrm {~kJ} \cdot \mathrm { mol } ^ { - 1 } \
1 / 2 \mathrm { Cl } _ { 2 } ( \mathrm {~g} ) \rightarrow \mathrm { Cl } ( \mathrm { g } ) & + 122 \mathrm {~kJ} \cdot \mathrm { mol } ^ { - 1 } \
\mathrm { Cl } ( \mathrm { g } ) \mathrm { e } ^ { - } \rightarrow \mathrm { Cl } ^ { - } ( \mathrm { g } ) & - 349 \mathrm {~kJ} \cdot \mathrm { mol } ^ { - 1 } \
\mathrm {~K} ( \mathrm {~s} ) + 1 / 2 \mathrm { Cl } _ { 2 } ( \mathrm {~g} ) \rightarrow \mathrm { KCl } ( \mathrm { s } ) & - 437 \mathrm {~kJ} \cdot \mathrm { mol } ^ { - 1 }
\end{array}$$

Accepted Answer

+717 kJ.mol^-¹

Question 4

Give $\Delta$Hr values for each of the following reactions from the information below.
$\Delta$Hf$\omicron $(HCl(g))= -92.31 kJ.mol-1 
H-Cl bond enthalpy = +431 kJ.mol-1 
O-H bond enthalpy = +463 kJ.mol-1 
$\Delta$Hf$\omicron $(H2O(g))= -241.8 kJ.mol-1 
(a)2H(g)+ O(g)$\rightarrow$H2O(g)
(b)H2(g)+ Cl2(g)$\rightarrow$ 2HCl(g)
(c)H(g)+ Cl(g)$\rightarrow$ HCl(g)

Accepted Answer

(a)-926 kJ.mol^-

Question 5

Water slowly evaporates at 25oC .Which of the following statements regarding this reaction is true?

Accepted Answer

A)  This is a spontaneous reaction that is entropy driven. 
B)  This is a spontaneous reaction that is enthalpy driven. 
C)  The signs of the reaction enthalpy and entropy, respectively, are + and +. 
D)  The signs of the reaction enthalpy and entropy, respectively, are - and -. 
E)  This reaction is spontaneous only at 100oC. 
A)  This is a spontaneous reaction that is entropy driven. 
B)  This is a spontaneous reaction that is enthalpy driven. 
C)  The signs of the reaction enthalpy and entropy, respectively, are + and +. 
D)  The signs of the reaction enthalpy and entropy, respectively, are - and -. 
E)  This reaction is spontaneous only at 100oC.

Question 6

For CO2(g)$\rightarrow$CO2(aq),is the entropy change positive or negative?

Accepted Answer

Question 7

Given the following standard reaction enthalpies:
O2(g)$\rightarrow$ 2O(g)
$\Delta$H° = +498.4 kJ.mol-1 
NO(g)+ O3(g)$\rightarrow$ NO2(g)+ O2(g)
$\Delta$H° = -200 kJ.mol-1 
And the standard enthalpy of formation of ozone,+142.7 kJ.mol-1 ,Calculate the standard reaction enthalpy for the reaction
NO(g)+ O(g)$\rightarrow$NO2(g)

Accepted Answer

A)  -306 kJ.mol-1  
B)  +355 kJ.mol-1  
C)  +592 kJ.mol-1  
D)  +555 kJ.mol-1  
E)  +192 kJ.mol-1  
A)  -306 kJ.mol-1  
B)  +355 kJ.mol-1  
C)  +592 kJ.mol-1  
D)  +555 kJ.mol-1  
E)  +192 kJ.mol-1

Question 8

Work is reported in joules; and 1 joule = ____________

Accepted Answer

1 kg.m<sup

Question 9

Calculate$\Delta$Ssurr° at 298 K for the reaction
6C(s)+ 3H2(g)$\rightarrow$C6H6(l)
$\Delta$Hr° = +49.0 kJ.mol-1,
$\Delta$Sr° = -253 J.K-1.mol-1

Accepted Answer

A)  +164 J.K-1.mol-1  
B)  -417 J.K-1.mol-1  
C)  +253 J.K-1.mol-1  
D)  -164 J.K-1.mol-1  
E)  -253 J.K-1.mol-1  
A)  +164 J.K-1.mol-1  
B)  -417 J.K-1.mol-1  
C)  +253 J.K-1.mol-1  
D)  -164 J.K-1.mol-1  
E)  -253 J.K-1.mol-1

Question 10

Which of the following has the lowest standard molar entropy?

Accepted Answer

A)  C(graphite) 
B)  P4(s) 
C)  S8(s) 
D)  C60(s) 
E)  C(diamond) 
A)  C(graphite) 
B)  P4(s) 
C)  S8(s) 
D)  C60(s) 
E)  C(diamond)

Question 11

When barium hydroxide is dissolved in water, the temperature of the solution increases.Which of the following statements regarding this reaction is true?

Accepted Answer

A)  The reaction is spontaneous at all temperatures. 
B)  The reaction is driven only by the entropy. 
C)  The reaction is driven only by the enthalpy. 
D)  The reaction is spontaneous only at low temperatures. 
E)  The reaction is spontaneous only at high temperatures. 
A)  The reaction is spontaneous at all temperatures. 
B)  The reaction is driven only by the entropy. 
C)  The reaction is driven only by the enthalpy. 
D)  The reaction is spontaneous only at low temperatures. 
E)  The reaction is spontaneous only at high temperatures.

Question 12

At constant pressure and temperature, which of the following statements is true for the reaction:
N2O5(s)$\rightarrow$ 2NO2(g)+ ½O2(g),
$\Delta$Hr = 109.5 kJ.mol-1  at 298 K.

Accepted Answer

A) $\Delta$H is independent of the physical states of the reactants. 
B)  $\Delta$H = $\Delta$U 
C)  w = 0 
D)  $\Delta$H  $\Delta$U 
A) $\Delta$H is independent of the physical states of the reactants. 
B)  $\Delta$H = $\Delta$U 
C)  w = 0 
D)  $\Delta$H  $\Delta$U

Question 13

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ .
How much energy did the system gain or lose as heat?

Accepted Answer

A)  The system lost 90 kJ of energy as heat. 
B)  The system lost 210 kJ of energy as heat. 
C)  The system gained 60 kJ of energy as heat. 
D)  The system gained 90 kJ of energy as heat. 
E)  The system gained 210 kJ of energy as heat. 
A)  The system lost 90 kJ of energy as heat. 
B)  The system lost 210 kJ of energy as heat. 
C)  The system gained 60 kJ of energy as heat. 
D)  The system gained 90 kJ of energy as heat. 
E)  The system gained 210 kJ of energy as heat.

Question 14

Calculate the lattice enthalpy of calcium oxide from the following data.
Enthalpy of formation of Ca(g): +178 kJ.mol-1 
First ionization energy of Ca(g): +590 kJ.mol-1 
Second ionization energy of Ca(g): +1150 kJ.mol-1 
Enthalpy of formation of O(g): +249 kJ.mol-1 
First electron affinity of O(g): +141 ($\Delta$H = kJ.mol-1 
Second electron affinity of O(g): -844 $\Delta$H = +844)kJ.mol-1 
Enthalpy of formation of CaO(s): -635 kJ.mol-1

Accepted Answer

A)  1817 kJ.mol-1  
B)  1391 kJ.mol-1  
C)  2235 kJ.mol-1  
D)  3754 kJ.mol-1  
E)  3505 kJ.mol-1  
A)  1817 kJ.mol-1  
B)  1391 kJ.mol-1  
C)  2235 kJ.mol-1  
D)  3754 kJ.mol-1  
E)  3505 kJ.mol-1

Question 15

The reaction 2C(s)+ 2H2(g)$\rightarrow$C2H4(g) is endothermic.This reaction will not be spontaneous at any temperature.

Accepted Answer

A) True 
 B)False

Question 16

When nitrogen gas expands from 3.00 to 6.00 L and 2.00 kJ of energy is transferred as heat to the nitrogen in a cylinder fitted with a piston at an external pressure of 2.00 atm, against this constant pressure,
What is $\Delta$U for the process?

Accepted Answer

A)  -0.608 kJ 
B)  +2.61 kJ 
C)  -2.61 kJ 
D)  0 
E)  +1.39 kJ 
A)  -0.608 kJ 
B)  +2.61 kJ 
C)  -2.61 kJ 
D)  0 
E)  +1.39 kJ

Question 17

Calculate $\Delta$Stotal for the isothermal irreversible free expansion of 1.00 mol of ideal gas from 8.00 L to 20.00 L at 298 K.

Accepted Answer

A)  0 
B)  +15.2 J.K-1.mol-1  
C)  +7.6 J.K-1.mol-1  
D) -15.2 J.K-1.mol-1  
E)  -7.6 J.K-1.mol-1  
A)  0 
B)  +15.2 J.K-1.mol-1  
C)  +7.6 J.K-1.mol-1  
D) -15.2 J.K-1.mol-1  
E)  -7.6 J.K-1.mol-1

Question 18

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s),Which enthalpy change(s)
Is/are endothermic?

Accepted Answer

A)  the lattice enthalpy of NaCl(s) 
B)  the electron affinity of chlorine 
C)  the reverse of the lattice enthalpy of NaCl(s) 
D)  All of the enthalpy changes are endothermic except for the standard enthalpy of formation of NaCl(s). 
A)  the lattice enthalpy of NaCl(s) 
B)  the electron affinity of chlorine 
C)  the reverse of the lattice enthalpy of NaCl(s) 
D)  All of the enthalpy changes are endothermic except for the standard enthalpy of formation of NaCl(s).

Question 19

Calculate the H-Br bond enthalpy given the standard enthalpies of formation for HBr(g), H(g),And Br(g): -36.2,218, And112kJ.mol-1 ,Respectively.

Accepted Answer

A)  320 kJ.mol-1  
B)  366 kJ.mol-1  
C)  124 kJ.mol-1  
D)  284 kJ.mol-1  
E)  196 kJ.mol-1  
A)  320 kJ.mol-1  
B)  366 kJ.mol-1  
C)  124 kJ.mol-1  
D)  284 kJ.mol-1  
E)  196 kJ.mol-1

Question 20

Calculate the Br-Br bond enthalpy given the standard enthalpies of formation for Br2(g) and Br(g),30.7 and 112 kJ.mol-1 ,Respectively.

Accepted Answer

A)  193 kJ.mol-1  
B)  255 kJ.mol-1  
C)  143 kJ.mol-1  
D)  81 kJ.mol-1  
E)  30.7 kJ.mol-1  
A)  193 kJ.mol-1  
B)  255 kJ.mol-1  
C)  143 kJ.mol-1  
D)  81 kJ.mol-1  
E)  30.7 kJ.mol-1

Which of the following statements is true?

Use the Boltzmann formula to calculate the entropy at T = 0 of 1.00 mol chlorobenzene, C₆H₅Cl,Where each molecule can be oriented in any of six ways.

Calculate the lattice enthalpy of potassium chloride given the following enthalpy data. ()\rightarrow() +89\cdot ()\rightarrow()+ +418\cdot 1/2()\rightarrow() +122\cdot ()\rightarrow() -349\cdot ()+1/2()\rightarrow() -437\cdot

Water slowly evaporates at 25^oC .Which of the following statements regarding this reaction is true?

For CO₂(g) $\rightarrow$ CO₂(aq),is the entropy change positive or negative?

Work is reported in joules; and 1 joule = ____________

Calculate $\Delta$ S_surr° at 298 K for the reaction 6C(s)+ 3H₂(g) $\rightarrow$ C₆H₆(l) $\Delta$ H_r° = +49.0 kJ.mol^-¹, $\Delta$ S_r° = -253 J.K^-¹.mol^-¹

Which of the following has the lowest standard molar entropy?

When barium hydroxide is dissolved in water, the temperature of the solution increases.Which of the following statements regarding this reaction is true?

At constant pressure and temperature, which of the following statements is true for the reaction: N₂O₅(s) $\rightarrow$ 2NO₂(g)+ ½O₂(g), $\Delta$ H_r = 109.5 kJ.mol^-¹ at 298 K.

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ . How much energy did the system gain or lose as heat?

The reaction 2C(s)+ 2H₂(g) $\rightarrow$ C₂H₄(g) is endothermic.This reaction will not be spontaneous at any temperature.

When nitrogen gas expands from 3.00 to 6.00 L and 2.00 kJ of energy is transferred as heat to the nitrogen in a cylinder fitted with a piston at an external pressure of 2.00 atm, against this constant pressure, What is $\Delta$ U for the process?

Calculate $\Delta$ S_total for the isothermal irreversible free expansion of 1.00 mol of ideal gas from 8.00 L to 20.00 L at 298 K.

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s),Which enthalpy change(s) Is/are endothermic?

Calculate the H-Br bond enthalpy given the standard enthalpies of formation for HBr(g), H(g),And Br(g): -36.2,218, And112kJ.mol^-¹,Respectively.

Calculate the Br-Br bond enthalpy given the standard enthalpies of formation for Br₂(g) and Br(g),30.7 and 112 kJ.mol^-¹,Respectively.

Atoms

Molecules

States of Matter

Equilibrium

Reactions

Kinetics

The Main-Group Elements

The D-Block Elements

Nuclear Chemistry

Organic Chemistry

Filters

Exam 4: Thermodynamics

Which of the following statements is true?

Use the Boltzmann formula to calculate the entropy at T = 0 of 1.00 mol chlorobenzene, C6H5Cl,Where each molecule can be oriented in any of six ways.

Calculate the lattice enthalpy of potassium chloride given the following enthalpy data. ()\rightarrow() +89\cdot ()\rightarrow()+ +418\cdot 1/2()\rightarrow() +122\cdot ()\rightarrow() -349\cdot ()+1/2()\rightarrow() -437\cdot

Water slowly evaporates at 25oC .Which of the following statements regarding this reaction is true?

For CO2(g) →\rightarrow→ CO2(aq),is the entropy change positive or negative?

Work is reported in joules; and 1 joule = ____________

Calculate Δ\DeltaΔ Ssurr° at 298 K for the reaction 6C(s)+ 3H2(g) →\rightarrow→ C6H6(l) Δ\DeltaΔ Hr° = +49.0 kJ.mol-1, Δ\DeltaΔ Sr° = -253 J.K-1.mol-1

Which of the following has the lowest standard molar entropy?

When barium hydroxide is dissolved in water, the temperature of the solution increases.Which of the following statements regarding this reaction is true?

At constant pressure and temperature, which of the following statements is true for the reaction: N2O5(s) →\rightarrow→ 2NO2(g)+ ½O2(g), Δ\DeltaΔ Hr = 109.5 kJ.mol-1 at 298 K.

A system had 150 kJ of work done on it and its internal energy increased by 60 kJ . How much energy did the system gain or lose as heat?

The reaction 2C(s)+ 2H2(g) →\rightarrow→ C2H4(g) is endothermic.This reaction will not be spontaneous at any temperature.

When nitrogen gas expands from 3.00 to 6.00 L and 2.00 kJ of energy is transferred as heat to the nitrogen in a cylinder fitted with a piston at an external pressure of 2.00 atm, against this constant pressure, What is Δ\DeltaΔ U for the process?

Calculate Δ\DeltaΔ Stotal for the isothermal irreversible free expansion of 1.00 mol of ideal gas from 8.00 L to 20.00 L at 298 K.

The standard enthalpy of formation of NaCl(s) is -411 kJ/mol.In a Born-Haber cycle for the formation of NaCl(s),Which enthalpy change(s) Is/are endothermic?

Calculate the H-Br bond enthalpy given the standard enthalpies of formation for HBr(g), H(g),And Br(g): -36.2,218, And112kJ.mol-1 ,Respectively.

Calculate the Br-Br bond enthalpy given the standard enthalpies of formation for Br2(g) and Br(g),30.7 and 112 kJ.mol-1 ,Respectively.

Atoms

Molecules

States of Matter

Equilibrium

Reactions

Kinetics

The Main-Group Elements

The D-Block Elements

Nuclear Chemistry

Organic Chemistry

Filters

Use the Boltzmann formula to calculate the entropy at T = 0 of 1.00 mol chlorobenzene, C₆H₅Cl,Where each molecule can be oriented in any of six ways.

Water slowly evaporates at 25^oC .Which of the following statements regarding this reaction is true?

For CO₂(g) $\rightarrow$ CO₂(aq),is the entropy change positive or negative?

Calculate $\Delta$ S_surr° at 298 K for the reaction 6C(s)+ 3H₂(g) $\rightarrow$ C₆H₆(l) $\Delta$ H_r° = +49.0 kJ.mol^-¹, $\Delta$ S_r° = -253 J.K^-¹.mol^-¹

At constant pressure and temperature, which of the following statements is true for the reaction: N₂O₅(s) $\rightarrow$ 2NO₂(g)+ ½O₂(g), $\Delta$ H_r = 109.5 kJ.mol^-¹ at 298 K.

The reaction 2C(s)+ 2H₂(g) $\rightarrow$ C₂H₄(g) is endothermic.This reaction will not be spontaneous at any temperature.

When nitrogen gas expands from 3.00 to 6.00 L and 2.00 kJ of energy is transferred as heat to the nitrogen in a cylinder fitted with a piston at an external pressure of 2.00 atm, against this constant pressure, What is $\Delta$ U for the process?

Calculate $\Delta$ S_total for the isothermal irreversible free expansion of 1.00 mol of ideal gas from 8.00 L to 20.00 L at 298 K.

Calculate the H-Br bond enthalpy given the standard enthalpies of formation for HBr(g), H(g),And Br(g): -36.2,218, And112kJ.mol^-¹,Respectively.

Calculate the Br-Br bond enthalpy given the standard enthalpies of formation for Br₂(g) and Br(g),30.7 and 112 kJ.mol^-¹,Respectively.