Practice Problem 4

Calculate the standard-state entropy of reaction for the following reactions and explain the sign of  S° for each reaction.

(a) Hg(l)  Hg(g)

(b) 2NO₂(g) N₂O₄(g)

(c) N₂(g) + O₂(g) 2NO(g)

Answer

(a)    98.94 J/K, the sign of  S^o is positive.

(b)  -175.83 J/K, the sign of S^o is negative.

(c)     24.77 J/K, the sign of S^o for this reaction is small but positive.