Question

which statement best describes how a catalyst can speed up a chemical reaction?
the catalyst decreases the activation energy needed.
the catalyst increases the concentration of products.
the catalyst binds to enzymes to release substrates.
the catalyst increases the concentration of reactants.

Explanation:

A catalyst speeds up a chemical reaction by lowering the activation energy. Activation energy is the minimum energy required for a reaction to occur. By reducing this energy barrier, more reactant molecules have sufficient energy to react, thus increasing the reaction rate.

• Increasing the concentration of products (\(2^{nd}\) option) does not speed up the forward reaction (it may even slow it down according to Le - Chatelier's principle in reversible reactions).
• Catalysts do not bind to enzymes to release substrates (\(3^{rd}\) option). Enzymes are biological catalysts themselves.
• Catalysts do not increase the concentration of reactants (\(4^{th}\) option). Concentration of reactants is usually controlled by the amount of reactants added to the reaction mixture.

Answer:

The catalyst decreases the activation energy needed.