Exothermic and Endothermic Reactions

Exothermic Reaction

A chemical reaction that releases energy, usually in the form of heat.

Endothermic Reaction

A chemical reaction in which energy is absorbed

What's the main difference between an exothermic and endothermic reaction?

An exothermic reaction releases energy and feels warm while an endothermic reaction absorbs energy and feels cool.

Sara mixed water and calcium chloride. The reaction made the water turn cloudy. The temperature of the reaction went from 23 degrees C to 52 degrees C. Is the reaction exothermic or endothermic?

Exothermic

Samuel mixed baking soda with hydrochloric acid. The reaction bubbled and the temperature went from 52 degrees C to 22 degrees C. Is the reaction exothermic or endothermic?

Endothermic

When lighting a candle, heat is released in the form of a flame. This is an example of what kind of reaction? Exothermic or Endothermic?

Exothermic

When melting an ice cube, energy is absorbed and used to melt the ice. This is an example of what kind of reaction? Exothermic or Endothermic?

Endothermic

When freezing water to make ice, energy is released allowing the water molecules to come together and freeze. This is an example of what kind of reaction? Exothermic or Endothermic?

Exothermic

When water evaporates, heat is absorbed and used to turn the water into water vapor. This is an example of what kind of reaction? Exothermic or Endothermic?

Exothermic

Are exothermic/endothermic reactions physical or chemical changes?

Chemical changes