Which of the following reactions represents an exothermic reaction? C 2S → CS 2, ΔH = 27,550 cal 2H 2O → 2H 2 O 2, ΔH = 58 kcal C (graphite) → C (diamond), ΔH = 0. 45 kcal NH 3(g) 12. 0 kcal → ½N 2(g) 3/2H 2(g) CH 4 2O 2 → CO 2 2H 2O 212,800 cal.

Which statement is actually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.