Reactants

Definition

Reactants are the starting substances that undergo chemical changes in a reaction. They are present before the reaction begins and are transformed into products.

5 Must Know Facts For Your Next Test

1. Reactants are consumed during a chemical reaction.
2. The amount of reactants determines the quantity of products formed.
3. Reactants can be elements, compounds, or molecules.
4. In a balanced chemical equation, reactants are listed on the left side.
5. The rate at which reactants are used up can affect the speed of the reaction.

Review Questions

• What role do reactants play in a chemical reaction?
• Where are reactants found in a balanced chemical equation?
• How do reactants affect the quantity of products formed?

Related terms

Products: Substances formed as a result of a chemical reaction.

Catalyst: A substance that speeds up a chemical reaction without being consumed.

Activation Energy: The minimum energy required for a chemical reaction to occur.