The hydrocarbon propene (CH3-CH=CH2) can react in two different ways with bromine (Chapters 12 and 14).
(i)

(ii)

(a) Using the bond strengths (kcal mol-1) given in the margin, calculate –³H° for each of these reactions, (b) –³So ‰ˆ 0 cal K-l mol-1 for one of these reactions and -35 cal K-l mol-1 for the other. Which reaction has which –³So? Briefly explain your answer, (c) Calculate –³G° for each reaction at 25°C and at 600°C. Are both of these reactions thermodynamically favorable at 25°C? At 600°C?

Br B CH,-CH-CH2 + Br2 CH,-CH-CH, + HBr Br