Energy Changes

What happens to heat in an exothermic change?

• taken in from the surroundings

• given out to the surroundings

What happens to heat in an endothermic change?

• taken in from the surroundings

• given out to the surroundings

All physical processes do not involve energy changes.

• True

• False

All chemical reactions involve energy changes.

• True

• False

What type of reaction occurs in a hand warmer?

• exothermic

• endothermic

What type of reaction occurs in a cold pack?

• exothermic

• endothermic

An endothermic change may be identified by a decrease in the temperature of the reaction mixture.

• True

• False

After mixing two chemicals, there is a change in the temperature of the reaction mixture from 25 °C to 33 °C. Which statement describes this reaction?

• It is an exothermic reaction.

• It is an endothermic reaction.

• There was an explosion between the two chemicals.

• One of the chemicals was burning.

A certain type of candy can fizz in your mouth and cause your tongue to feel cold. What is the reason for this experience?

• There is an exothermic change.

• There is an endothermic change.

• The candy contains ice.

• The candy has substances that the tongue is sensitive to.

What statement describes an exothermic reaction?

• Products have more energy than reactants.

• Products have less energy than reactants.

• Products have the same energy as reactants.

• It is not possible to determine energy differences between products and reactants.