Physical science worksheet matching match each item with the correct term below. a. activation energy f. inhibitor b. catalyst g. product c. chemical reaction h. rate of reaction d. endothermic reaction a. reactant in. exothermic reaction 1. process that produces chemical change 2. substance that slows down a chemical reaction 3. reaction in which heat energy is absorbed 4. substance that exists before a chemical reaction begins 5. minimum amount of energy needed in order for a reaction to begin 6. substance formed by a chemical reaction 7. substance that speeds up a chemical reaction 8. reaction in which heat energy is released