What does stoichiometry calculate in chemical reactions?

Stoichiometry is fundamentally concerned with the quantitative relationships between reactants and products in a chemical reaction. It enables chemists to calculate the amounts (mass) of reactants needed or the amounts of products formed based on balanced chemical equations. By using mole ratios derived from these equations, stoichiometry allows for precise predictions of how much of a substance is consumed and how much is produced during a reaction, making it crucial for planning and optimizing chemical processes.

In contrast, while the rate of chemical reactions, energy changes, and the volume of gases produced are important aspects of chemistry, they represent different areas of study. The rate of reactions pertains to kinetics, energy changes involve thermodynamics, and gas volume calculations often include considerations like the ideal gas law. These areas are not the primary focus of stoichiometry, which is centered specifically on the mass and mole relationships in reactions. Thus, the focus on calculating the mass of reactants and products underscores the role stoichiometry plays in understanding the quantitative aspects of chemical reactions.