Question

A catalyst increases the rate of a reaction by lowering EA _____.

1) and thus making ΔG more negative
2) without having any effect on ΔG
3) and thus shifting the equiLiBrium
4) and thus increasing the chance that reactants will collide

Answer 1

A catalyst increases a chemical reaction rate by lowering the activation energy without affecting the change in Gibbs free energy (ΔG), so it does not alter the energetics of the reactants or products or the equilibrium of the reaction.

Step-by-step explanation:

A catalyst is a substance that increases the rate of a chemical reaction by providing a new pathway with a lower activation energy (Ea). It does so without altering the energy of reactants or the products, meaning it has no effect on the change in Gibbs free energy (ΔG) for the reaction. Therefore, the correct answer is that a catalyst increases the rate of a reaction by lowering Ea without having any effect on ΔG.

The presence of a catalyst allows a greater percentage of reactant molecules to have effective collisions, which increases the reaction rate. However, it does not change the overall energy change of the reaction itself, nor does it solely increase the chances of collisions without lowering the activation energy.

Moreover, the presence of a catalyst does not shift the equilibrium of the reaction; rather, it helps the system to reach equilibrium more quickly. This is because a catalyst affects both the forward and reverse reactions equally, speeding up the rates of both directions without altering their relative favorability as determined by ΔG.