Question

Which of the following are present both before and after a chemical reaction?

Answer 1

That would be a catalyst, it makes the reaction faster.

Answer 2

Catalysts is wrong because it is never in the chemical equation. It only speeds up the reactions. A is wrong because reactants are only before the chemical reaction. D is wrong because products are only after the chemical reaction. It's C because the energy is still in the molecules and is not lost when it goes through the chemical reaction. Hope this helps! ;)