State whether the following processes are endothermic or exothermic and explain why?

a) Combustion of coal
b) Vapourization of alcohol
c) Freezing of sodium liquid
d) Sublimation of dry ice (solid carbon dioxide)

1 Answer

a) Exothermic
b) Endothermic
c) Exothermic
d) Endothermic

Explanation:

a) and c) are exothermic because the particles are losing heat energy. Therefore, heat is being given off to the surroundingĀ·

b) and d) endothermic because they require the surroundings to supply heat energy for the reaction to happen.

Tyler Dewitt on YouTube is an excellent watch for exothermic and exothermic reactions.

Here's one of them.