Chemical Reactions Quiz

What happens during a chemical reaction?

• Substances are combined or break apart to form new substances.

• New atoms are created and old ones are destroyed.

• Substances change state but stay the same.

• Energy is never involved in chemical reactions.

Which of the following is true about many chemical reactions?

• They are reversible, and the original substances can always be recovered.

• They are irreversible, meaning the original substances cannot easily be recovered.

• They only occur in laboratories.

• They happen without any change in substances.

What happens to atoms during a chemical reaction?

• They are destroyed and new ones are created.

• They are rearranged to form new substances.

• They stay in the same positions.

• They combine without forming new products.

Which of these is NOT a sign of a chemical reaction?

• A change in color

• Formation of bubbles (gas release)

• A change in temperature

• A change in state from solid to liquid

What is an exothermic reaction?

• A reaction that absorbs energy.

• A reaction that releases energy.

• A reaction that forms a precipitate.

• A reaction that only happens in living things.

What is an endothermic reaction?

• A reaction that releases energy.

• A reaction that absorbs energy.

• A reaction that creates a solid.

• A reaction that always produces light.

What is combustion?

• A reaction where a substance burns in oxygen.

• A reaction where a compound breaks down using heat.

• A reaction where a base reacts with water.

• A reaction that happens without energy release.

What is oxidation?

• When a substance gains oxygen.

• When a substance loses oxygen.

• When a substance reacts with water.

• When a substance decomposes with heat.

What happens to mass during a chemical reaction?

• Mass is created.

• Mass is destroyed.

• Mass stays the same.

• Mass is lost to the surroundings.

Why must chemical equations be balanced?

• To ensure the conservation of mass.

• To make the reaction reversible.

• To ensure the reaction happens faster.

• To avoid energy changes in the reaction.