Question 1

For Br2(l), the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

Accepted Answer

Question 2

An example of a spontaneous process having $\Delta$H ~ 0 is

Accepted Answer

A)  1 L He(1 atm, 298 K) + 1 L Ar(1 atm, 298 K) $\rightarrow$ 2 L He/Ar mixture(1 atm, 298 K). 
B)  evaporation of water at 100$\omicron$C and 1 atm. 
C)  a ball rolling from the top of a hill to the bottom of a valley. 
D)  precipitation of AgBr(s) from a solution of Ag+(aq) and Br-(aq). 
E)  freezing of water at -$\omicron$C. 
A)  1 L He(1 atm, 298 K) + 1 L Ar(1 atm, 298 K) $\rightarrow$ 2 L He/Ar mixture(1 atm, 298 K). 
B)  evaporation of water at 100$\omicron$C and 1 atm. 
C)  a ball rolling from the top of a hill to the bottom of a valley. 
D)  precipitation of AgBr(s) from a solution of Ag+(aq) and Br-(aq). 
E)  freezing of water at -$\omicron$C.

Question 3

Determine $\Delta$Hf$\omicron $(HCl(g)) from the following data.
H-Cl bond enthalpy = +431 kJ.mol-1 
$\Delta$Hf$\omicron $(H(g))= +217.9 kJ.mol-1 
$\Delta$Hf$\omicron $(Cl(g))= +121.4 kJ.mol-1

Accepted Answer

A)  +92 kJ.mol-1  
B)  -261 kJ.mol-1  
C) -431 kJ.mol-1  
D)  +431 kJ.mol-1  
E)  -92 kJ.mol-1  
A)  +92 kJ.mol-1  
B)  -261 kJ.mol-1  
C) -431 kJ.mol-1  
D)  +431 kJ.mol-1  
E)  -92 kJ.mol-1

Question 4

Use tabulated thermodynamic data to calculate the concentration of CO2(aq)
in equilibrium with an external pressure of 2.50 atm CO2(g) at 298 K.

Accepted Answer

Question 5

The reaction N2(g)+3H2(g)$\rightarrow$ 2NH3(g)is exothermic.This reaction will be spontaneous at all temperatures.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following would have the largest calculated value of the residual entropy?

Accepted Answer

A)  C6H5Cl(s) (chlorobenzene) 
B)  CO(s) 
C)  N2O(s) 
D)  FClO3(s) 
E)  CCl4(s) 
A)  C6H5Cl(s) (chlorobenzene) 
B)  CO(s) 
C)  N2O(s) 
D)  FClO3(s) 
E)  CCl4(s)

Question 7

What can an isolated system exchange with the surroundings?

Accepted Answer

A)  Energy only 
B)  Matter only 
C)  Energy and matter 
D)  Neither energy or matter 
E)  None of the above 
A)  Energy only 
B)  Matter only 
C)  Energy and matter 
D)  Neither energy or matter 
E)  None of the above

Question 8

Which of the following statements is true?

Accepted Answer

A)  The molar entropy does not depend on the structure of the compound. 
B)  The molar entropy of H2O(l) is about the same as the molar entropy of ice. 
C)  An isothermal process that leads to a decrease in free energy is spontaneous. 
D)  If $\Delta$GrS1U1P1$\circ$S1S1P0
 > 0, then the reaction is spontaneous. 
E)  All processes that give positive changes in energy are spontaneous. 
A)  The molar entropy does not depend on the structure of the compound. 
B)  The molar entropy of H2O(l) is about the same as the molar entropy of ice. 
C)  An isothermal process that leads to a decrease in free energy is spontaneous. 
D)  If $\Delta$GrS1U1P1$\circ$S1S1P0
 > 0, then the reaction is spontaneous. 
E)  All processes that give positive changes in energy are spontaneous.

Question 9

Calculate the final temperature when 2.50 kJ of energy is transferred as heat to 1.50 mol BF3 at 298 K and 1 atm at constant pressure.

Accepted Answer

A)  82S1U1P1$\circ$S1S1P0C 
B)  80S1U1P1$\circ$S1S1P0C 
C)  159S1U1P1$\circ$S1S1P0C 
D)  75S1U1P1$\circ$S1S1P0C 
E)  92S1U1P1$\circ$S1S1P0C 
A)  82S1U1P1$\circ$S1S1P0C 
B)  80S1U1P1$\circ$S1S1P0C 
C)  159S1U1P1$\circ$S1S1P0C 
D)  75S1U1P1$\circ$S1S1P0C 
E)  92S1U1P1$\circ$S1S1P0C

Question 10

For a given transfer of energy, a greater change in disorder occurs when the temperature is high.

Accepted Answer

A) True 
 B)False

Question 11

All the following compounds become less stable with respect to their elements as the temperature is raised except

Accepted Answer

A)  PCl5(g). 
B)  C6H12(l). 
C)  N2H4(l). 
D)  CuO(s). 
E)  HCN(g). 
A)  PCl5(g). 
B)  C6H12(l). 
C)  N2H4(l). 
D)  CuO(s). 
E)  HCN(g).

Question 12

Consider the reaction
2SO3(g)$\rightarrow$2SO2(g)+ O2(g)
Which statement is true for this reaction?

Accepted Answer

A)  $\Delta$S  0 
C)  $\Delta$S = 0 
D)  Smo = 0 for O2(g) 
A)  $\Delta$S  0 
C)  $\Delta$S = 0 
D)  Smo = 0 for O2(g)

For Br₂(l), the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

An example of a spontaneous process having $\Delta$ H ~ 0 is

Determine $\Delta$ H_f^$\omicron$(HCl(g)) from the following data. H-Cl bond enthalpy = +431 kJ.mol^-¹ $\Delta$ H_f^{$\omicron$ (}H(g))= +217.9 kJ.mol^-¹ $\Delta$ H_f^$\omicron$(Cl(g))= +121.4 kJ.mol^-¹

Use tabulated thermodynamic data to calculate the concentration of CO₂(aq) in equilibrium with an external pressure of 2.50 atm CO₂(g) at 298 K.

The reaction N₂(g)+3H₂(g) $\rightarrow$ 2NH₃(g)is exothermic.This reaction will be spontaneous at all temperatures.

Which of the following would have the largest calculated value of the residual entropy?

What can an isolated system exchange with the surroundings?

Which of the following statements is true?

Calculate the final temperature when 2.50 kJ of energy is transferred as heat to 1.50 mol BF₃ at 298 K and 1 atm at constant pressure.

For a given transfer of energy, a greater change in disorder occurs when the temperature is high.

All the following compounds become less stable with respect to their elements as the temperature is raised except

Consider the reaction 2SO₃(g) $\rightarrow$ 2SO₂(g)+ O₂(g) Which statement is true for this reaction?

Atoms

Molecules

States of Matter

Equilibrium

Reactions

Kinetics

The Main-Group Elements

The D-Block Elements

Nuclear Chemistry

Organic Chemistry

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Exam 4: Thermodynamics

For Br2(l), the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

An example of a spontaneous process having Δ\DeltaΔ H ~ 0 is

Determine Δ\DeltaΔ Hf ο\omicron ο (HCl(g)) from the following data. H-Cl bond enthalpy = +431 kJ.mol-1 Δ\DeltaΔ Hf ο\omicron ο (H(g))= +217.9 kJ.mol-1 Δ\DeltaΔ Hf ο\omicron ο (Cl(g))= +121.4 kJ.mol-1

Use tabulated thermodynamic data to calculate the concentration of CO2(aq) in equilibrium with an external pressure of 2.50 atm CO2(g) at 298 K.

The reaction N2(g)+3H2(g) →\rightarrow→ 2NH3(g)is exothermic.This reaction will be spontaneous at all temperatures.

Which of the following would have the largest calculated value of the residual entropy?

What can an isolated system exchange with the surroundings?

Which of the following statements is true?

Calculate the final temperature when 2.50 kJ of energy is transferred as heat to 1.50 mol BF3 at 298 K and 1 atm at constant pressure.

For a given transfer of energy, a greater change in disorder occurs when the temperature is high.

All the following compounds become less stable with respect to their elements as the temperature is raised except

Consider the reaction 2SO3(g) →\rightarrow→ 2SO2(g)+ O2(g) Which statement is true for this reaction?

Atoms

Molecules

States of Matter

Equilibrium

Reactions

Kinetics

The Main-Group Elements

The D-Block Elements

Nuclear Chemistry

Organic Chemistry

Filters

For Br₂(l), the standard enthalpy of formation is ______________________ (positive/ negative/ zero).

An example of a spontaneous process having $\Delta$ H ~ 0 is

Determine $\Delta$ H_f^$\omicron$(HCl(g)) from the following data. H-Cl bond enthalpy = +431 kJ.mol^-¹ $\Delta$ H_f^{$\omicron$ (}H(g))= +217.9 kJ.mol^-¹ $\Delta$ H_f^$\omicron$(Cl(g))= +121.4 kJ.mol^-¹

Use tabulated thermodynamic data to calculate the concentration of CO₂(aq) in equilibrium with an external pressure of 2.50 atm CO₂(g) at 298 K.

The reaction N₂(g)+3H₂(g) $\rightarrow$ 2NH₃(g)is exothermic.This reaction will be spontaneous at all temperatures.

Calculate the final temperature when 2.50 kJ of energy is transferred as heat to 1.50 mol BF₃ at 298 K and 1 atm at constant pressure.

Consider the reaction 2SO₃(g) $\rightarrow$ 2SO₂(g)+ O₂(g) Which statement is true for this reaction?