Question

In terms of energy, how would you classify the following chemical reaction?
2Cu + O2 +315 KJ---> 2CuO A.endothermic
B.exothermic
C. both endothermic and exothermic
D. Neither endothermic nor exothermic

Answer 1

it's exothermic because the KJ are on the reactants side and you get 2CuO on the products side, the energy is being released into its surroundings 

Answer 2

it's exothermic because the kg are on the reactants side and you get 2cuo