Final answer:
In chemical reactions, reactants are the starting materials and products are the substances formed as a result. To identify them, their chemical formulae are noted and an equation is written with reactants on the left and products on the right, ensuring the equation is balanced to comply with the Law of Conservation of Mass.
Step-by-step explanation:
To identify the reactants and products in a chemical reaction, we must closely examine the reaction's equation. Reactants are substances that start the reaction, and products are substances that are produced by the reaction. Using the example of combustion of sugar, the reactants are sugar (C6H12O6) and oxygen gas (O2), which combine to produce the products: carbon dioxide (CO2) and water (H2O). The reaction can be represented by the equation: C6H12O6 + O2 → CO2 + H2O.
The first step in writing a chemical equation is to identify the reactants and products and write their chemical formulae. Then, we arrange them with reactants on the left side of the arrow and the products on the right side. Chemical equations must reflect the Law of Conservation of Mass, meaning the total mass of the reactants must equal the total mass of the products. Therefore, we may need to balance the equation by adjusting coefficients—numerical multipliers in front of the chemical formulae—to ensure that the number of atoms for each element is the same on both sides.