Question

Which of the following statements is true?

A) Entropy is not a state function.

B) Endothermic processes decrease the entropy of the surroundings, at constant T and P.

C) Endothermic processes are never spontaneous.

D) Exothermic processes are always spontaneous.

E) None of the above are true.

Answer 1

E) None of the above are true.

Step-by-step explanation:

The spontaneity of a reaction depends on the Gibbs free energy (ΔG).

• If ΔG < 0 the reaction is spontaneous.
• If ΔG > 0 the reaction is nonspontaneous.

ΔG depends on the enthalpy (ΔH) and on the entropy (ΔS), according to the following expression.

ΔG = ΔH - T.ΔS

where,

T is the absolute temperature.

Which of the following statements is true?

A) Entropy is not a state function. FALSE. Entropy is a state function, which means that it only depends on the initial and final state of a process.

B) Endothermic processes decrease the entropy of the surroundings, at constant T and P. FALSE. Whether a reaction is endothermic or exothermic depends on the enthalpy and it is not related to the entropy. In endothermic processes, ΔH > 0 and in exothermic ones ΔH < 0.

C) Endothermic processes are never spontaneous. FALSE. If ΔS > 0 and |T.ΔS| > |ΔH|, the reaction is spontaneous even if ΔH > 0 because ΔG < 0.

D) Exothermic processes are always spontaneous. FALSE. If ΔS < 0 and |T.ΔS| > |ΔH|, the reaction is nonspontaneous even if ΔH < 0 because ΔG > 0.