Chemical Reactions and Equations

Activation energy is the minimum amount of energy needed for a chemical reaction to begin.

• True
• False

A chemical reaction in which more energy is absorbed than is released is endothermic.

• True
• False

Chemical equations are balanced by changing the subscripts of the molecules.

• True
• False

Exothermic reactions do not require any activation energy.

• True
• False

All chemical reactions occur at the same rate.

• True
• False

Energy is needed to break bonds in chemical reactions.

• True
• False

When a chemical equation contains the same number of atoms on both sides, the equation is balanced.

• True
• False

According to the law of conservation of mass, three atoms of calcium can react to produce six atoms of calcium.

• True
• False

All types of chemical reactions involve(s) a substance combining with oxygen and releasing energy.

• True
• False

This diagram models a replacement reaction.

• True
• False