Final answer:
In a chemical equation, the reactants are on the left-hand side and the products are on the right-hand side with an arrow in between. A catalyst should be represented above or below the arrow to indicate its presence.
Step-by-step explanation:
In a chemical equation, the reactants are written on the left-hand side and the products are written on the right-hand side of the equation. The arrow in between the reactants and products represents the direction of the reaction. If a catalyst is present in the chemical reaction, it should be written above or below the arrow to indicate its presence.