Classify the following as an endothermic or exothermic reaction:

a. making popcorn in a microwave oven.

b. a burning match.

c. boiling water.

d. burning rocket fuel.

e. the reaction inside a heat pack

a. making popcorn in a microwave oven. Endothermic

b. a burning match. Exothermic

c. boiling water. Endothermic

d. burning rocket fuel. Exothermic

e. the reaction inside a heat pack Exothermic

Explanation:

In order to answer, we need to review the definitions of exothermic and endothermic reactions.

Exothermic reactions give out heat. They cause increase in the energy of the system.

Endothermic reactions absorb heat. They cause decrease in the energy of system.

By this definition,

a. making popcorn in a microwave oven. Endothermic as heat energy is provided to the corn which causes it to pop.

b. a burning match. Exothermic as heat energy is given out by a burning match.

c. boiling water. Endothermic as heat energy is provided to the water which causes it to boil.

d. burning rocket fuel. Exothermic as heat energy is given out by burning fuel.

e. the reaction inside a heat pack. Exothermic as reaction which takes place inside heat pack gives out heat. This heat provides comfort to painful joints and muscles.