Question 1

In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair, unless stated otherwise.

Accepted Answer

A)  1 mole of F2(g); 1 mole of Cl2(g) 
B)  1 mole of I2(s); 1 mole of I2(g) 
C)  1 mole of CaCO3(s); 1 mole of CaO(s) plus 1 mole of CO2(g) 
D)  1 mole of H2(g) at 25 $\degree$C; 1 mole of H2(g) at 50 $\degree$C 
E)  1 mole of O3(g); 1 mole of O2(g)

Question 2

Given: H2O(l) $\rightarrow$ H2O(g), $\Delta$H$\degree$ = 40.7 kJ at 373K, what is the entropy change in the system ($\Delta$S) when one mole of water vaporizes at 100$\degree$C and a pressure of one atmosphere?

Accepted Answer

A)  407 J/K 
B)  -407 J/K 
C)  109 J/K 
D)  -109 J/K 
E)  J/K

Question 3

Consider the reaction  If the concentrations of the Cu+ and I¯ ions in equilibrium at 298 K are both equal to 1.03 *10¯6 M, what is the value of $\Delta$G$\degree$for the reaction?

Accepted Answer

A)  -68 kJ 
B)  68 kJ 
C)  -30. kJ 
D)  30 kJ 
E)  34 kJ

Question 4

For a chemical reaction to be spontaneous only at high temperatures, which of the following conditions must be met?

Accepted Answer

A)  ($\Delta$S$\degree$  > 0, $\Delta$H$\degree$> 0) 
B)  ($\Delta$S$\degree$   > 0, $\Delta$H$\degree$  0) 
E)  ($\Delta$G $\degree$ > 0)

Question 5

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25 $\degree$C.

Accepted Answer

A)  CO(g), CO2(g) 
B)  NaCl(s), NaCl(aq) 
C)  H2S(g), H2S(aq) 
D)  Li(s), Pb(s) 
E)  H2(g), H2O(g)

Exam 20: Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair, unless stated otherwise.

Given: H₂O(l) $\rightarrow$ H₂O(g) , $\Delta$ H $\degree$ = 40.7 kJ at 373K, what is the entropy change in the system ( $\Delta$ S) when one mole of water vaporizes at 100 $\degree$ C and a pressure of one atmosphere?

For a chemical reaction to be spontaneous only at high temperatures, which of the following conditions must be met?

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25 $\degree$ C.

Exam 20: Thermodynamics: Entropy, Free Energy, and the Direction of Chemical Reactions

In which one of these pairs will the entropy of the first substance be greater than that of the second? Assume P and T are the same for each pair, unless stated otherwise.

Given: H2O(l) →\rightarrow→ H2O(g) , Δ\DeltaΔ H °\degree° = 40.7 kJ at 373K, what is the entropy change in the system ( Δ\DeltaΔ S) when one mole of water vaporizes at 100 °\degree° C and a pressure of one atmosphere?

Consider the reaction If the concentrations of the Cu+ and I¯ ions in equilibrium at 298 K are both equal to 1.03 *10¯6 M, what is the value of Δ\DeltaΔ G °\degree° for the reaction?

For a chemical reaction to be spontaneous only at high temperatures, which of the following conditions must be met?

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25 °\degree° C.

Given: H₂O(l) $\rightarrow$ H₂O(g) , $\Delta$ H $\degree$ = 40.7 kJ at 373K, what is the entropy change in the system ( $\Delta$ S) when one mole of water vaporizes at 100 $\degree$ C and a pressure of one atmosphere?

Which of the following pairs has the member with the greater molar entropy listed first? All systems are at 25 $\degree$ C.