CHEMISTRY 102 HWKTEST#7[g]
CURRENT DATE and TIME

For a reaction if ΔG° = 0, then

Your answer:
ΔH° = 0.
K = 1.
K = 0.
ΔS° = 0.
ΔG° = 0.


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What is the minimum temperature required for the spontaneous conversion of CCl₄(l) to CCl₄(g) when ΔH° is 573 kJ/mol and ΔS° is 1.64 kJ/(mol·K)?

Your answer:
215°C
349°C
89°C
76°C
189°C


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For the reaction 4Ag(s) + O₂(g) → 2Ag₂O(s) at 25°C and 1 atm of pressure, ΔH° is -61140 J and ΔS° is -132 J/K. For this problem, assume that ΔH° and ΔS° are essentially temperature independent. Which of the following statements is true?

Your answer:
The change in entropy is the driving force at low temperatures.
The reaction will be spontaneous at low temperatures, and the reverse reaction will be spontaneous at high temperatures.
The reaction will not be spontaneous at all temperatures.
The reaction will be spontaneous at all temperatures.
The reaction will be spontaneous at high temperatures, and the reverse reaction will be spontaneous at low temperatures.


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For the reaction PCl₅(g) → PCl₃(g) + Cl₂(g) at 1 atm of pressure, the value of ΔH is positive and the process is spontaneous at 250°C. Which of the following statements concerning this reaction is true?



1. The reverse reaction is endothermic.
2. The reverse reaction is nonspontaneous at room temperature.
3. The change in entropy is the driving force for the decomposition of PCl₅.

Your answer:
2 only
1, 2, and 3
1 only
3 only
1 and 2 only


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For the reaction CaCO₃(g) → CaO(s) + O₂(g) at 1 atm pressure, the values of ΔH and ΔS are both positive, and the process is spontaneous at 900°C. Which of the following statements about this reaction is true?

Your answer:
The change in entropy is the griving force for the reaction.
The reverse reaction is nonspontaneous at room temperature.
The reverse process is endothermic.
ΔG at room temperature is negative.
The process is exothermic at 900°C and endothermic at room temperature.


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For the reaction 3C(s) + 4H₂(g) C₃H₈(g),



ΔS° = -269 J/(mol·K)

ΔH° = 103.8 kJ/mol



Calculate the equilibrium constant at 25°C for the reaction above.

Your answer:
none of these
1.0 x 10¹⁷
1.0
2.1 x 10³²
3.7 x 10¹⁹


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Consider the following reaction, which is spontaneous at room temperature:



NH₃(g) + BF₃(g) → H₃N:BF₃(s)

One would predict that

Your answer:
ΔH is + and ΔS is + for the reaction.
ΔH is - and ΔS is + for the reaction.
ΔG is - at all temperatures.
ΔH is - and ΔS is - for the reaction.
ΔH is + and ΔS is - for the reaction.


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