APFIVE Standard Entropy Change of Reaction
For the reaction: 2NO(g) + O₂(g) → 2NO₂(g), the standard molar entropies are: S°[NO(g)] = 210.8 J/mol·K, S°[O₂(g)] = 205.1 J/mol·K, and S°[NO₂(g)] = 240.1 J/mol·K. Which statement correctly explains the sign of ΔS°rxn?
A
ΔS°rxn is positive because the reaction is spontaneous
B
ΔS°rxn is positive because NO₂ has higher entropy than NO
C
ΔS°rxn is negative because NO₂ has lower entropy than NO
D
ΔS°rxn is negative because there is a decrease in moles of gas