Which term refers to a substance that speeds up the rate of a chemical reaction?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by providing an alternative pathway for the reaction that has a lower activation energy, making it easier for the reactants to convert into products. This means that more molecules can successfully collide with enough energy to react, thereby increasing the reaction rate.

In various chemical reactions, catalysts play a crucial role in both industrial applications and biological systems. For instance, in biological systems, enzymes act as catalysts to facilitate metabolic reactions. In industrial processes, catalysts are employed to optimize the efficiency of chemical production.

The other terms do not fit the definition of a substance that accelerates a reaction. A reactant is a starting material in a chemical reaction, a solvent is a substance that dissolves a solute (usually in a solution), and an inhibitor slows down or prevents a reaction, which is the opposite of what a catalyst does.