Question

A catalyst changes the rate of a chemical reaction by?

1) changing the products of the reaction
2) changing the reactants involved in the reaction
3) increasing the frequency of molecular reactions
4) lowering the activation energy

Answer 1

A catalyst increases the rate of a chemical reaction by providing an alternative reaction pathway with lower activation energy, allowing more reactant molecules to effectively collide, thus speeding up the reaction. Therefore, correct option is 4.

Step-by-step explanation:

A catalyst changes the rate of a chemical reaction by lowering the activation energy needed for the reaction to proceed. It facilitates this by providing an alternative reaction pathway with a lower activation energy barrier.

This allows for a greater percentage of reactant molecules to have effective collisions, which results in an increased reaction rate. Catalysis does not change the reactants or products; instead, it works by changing the reaction mechanism.

Furthermore, catalysts remain unchanged after the reaction, meaning they are not consumed and can be used repeatedly. In biological processes, special catalysts called enzymes function in a similar way to regulate chemical reactions under physiological conditions.