What is a substance that speeds up the rate of a chemical reaction called?

A substance that speeds up the rate of a chemical reaction is known as a catalyst. Catalysts function by lowering the activation energy required for a reaction to proceed, thus increasing the reaction rate without being consumed in the process. They are crucial in various biological and chemical processes, allowing reactions to occur more efficiently and often under milder conditions than would otherwise be necessary.

Enzymes, while also catalysts, are specific types of catalysts that are proteins and facilitate biochemical reactions in living organisms. However, the term "catalyst" is broader and applies to both biological and non-biological catalysts. Inhibitors are substances that decrease reaction rates by obstructing or interfering with the catalytic action. Substrates are the reactants that undergo change during a reaction. Understanding these distinctions clarifies why the term "catalyst" is the most accurate answer to the question regarding the acceleration of chemical reactions.