Catalyst vs. Increasing concentration?

Question

Why is the effect on reaction rate of introducing a catalyst much greater than the effect of increasing concentration?


Thanks!

Answer 1

All reactions require a certain amount of threshold energy (known as activation energy)... a catalyst is going to accelerate a reaction by decreasing the amount of activiation energy required for the reaction to occur. By increasing the concentration of certain reactants, you will increase the rate of the reaction; however, the speed will not be as fast, b/c a large amount of energy will still be needed to start the process.

Answer 2

Because the catalyst makes the energy of activation for reaction to occur much lower than without it. Increasing the concentration depends more on statistical probability of encounters of reacting molecules. Lowering the energy is more efficient.

The lowering of activation of energy may come from a variety of factors as making reactants sterically favored, immobilized more for greater interaction, chemically changing the electrophilicity or nucleophilicity of the reactants, etc. all contributing to lower energy.

Answer 3

Theoritically, this statement is incorrect. However, in the reality, since the increasing concentration can only have an impact of increased of probability of molecular collisions where introducting a catalyst can introduct an entra path to the reactant to product. Also, it will increase the probability of ''sucessful'' collisions. Anyways, the best way to determine the application of a chemical system is by experiment.

Answer 4

Catalysts make individual chemical bonds more available for rxn than simply flooding the rxn with more reactant. Catalysts lower the activation energy and concentration doesn't.