Which term refers to the speed at which reactants are converted into products?

reaction rate

activation energy

meta stable state

spontaneous reaction

Reaction rate or rate of reaction.

Explanation:

The reaction rate is how first the reactants change into the product in a chemical reaction. As the reaction proceeds, there is a change in the concentration of reactants and the products. The rate of the reaction affected by various factors. These factors increase the reaction rate. The factors are pressure, temperature, catalysts, etc. As the temperature and pressure increase, the reaction rate also increases. But there is an optimum limit of these factors to increase the rate of reaction and beyond this limit, the reaction rate drops. Enzymes act as the catalyst which increases the rate of reaction.

reaction rate (first choice)