Question

In terms of energy, how would you classify the following reaction?
C2H6 + 137 kJ --> C2H4 + H2

Answer 1

I think this is getting at endothermic and exothermic reactions. Endothermic reactions need energy but exothermic reactions produce energy. So endothermic ones have energy before the arrow and exothermic reactions would have energy indicated after the arrow. I hope this clears up your question, if not reply and I'll see what I can do.