## Catalysts and Rates

Arrhenius Equation: $\ln k = - \frac{E_{a}}{RT} + \ln A$

alicechien_4F
Posts: 104
Joined: Sat Jul 20, 2019 12:15 am

### Catalysts and Rates

How come catalysts don't have an effect on the rate of the overall reaction if it lowers the activation energy?

Shail Avasthi 2C
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

### Re: Catalysts and Rates

Catalysts DO speed up reactions. You're right that catalysts lower activation energy by providing an alternate mechanism for the reaction. If you look at the exponential form of the Arrhenius equation, when you decrease activation energy, you are increasing the rate of the reaction exponentially.

PranaviKolla2B
Posts: 114
Joined: Fri Aug 30, 2019 12:17 am

### Re: Catalysts and Rates

Do we need to know what examples of common catalysts are?

Vincent Leong 2B
Posts: 207
Joined: Fri Aug 09, 2019 12:15 am

### Re: Catalysts and Rates

they do have an effect. catalysts lowerr the Ea for both the forward and reverse rxns and thus the rxn would happen faster in both the forward and reverse rxns. Therefore the rate of the entire reaction would increase. Look at rxn profile to help you visualize what happens --> it would make a lot more sense seeing how the rxn pathyway changes with a catalyst.

John Liang 2I
Posts: 102
Joined: Fri Aug 30, 2019 12:18 am

### Re: Catalysts and Rates

Catalysts indeed affect the rate of chemical rxns. By lowering Ea, the Arrhenius equation k=Ae^(-Ea/RT) will increase k and increase the rate. hope this helps

lauraxie2e
Posts: 108
Joined: Fri Aug 09, 2019 12:17 am

### Re: Catalysts and Rates

They do have an effect on reactions.

rohun2H
Posts: 100
Joined: Wed Sep 18, 2019 12:19 am

### Re: Catalysts and Rates

Catalyst will increase the rate of forwarding reaction by lowering activation energy.

Alfred Barrion 2H
Posts: 100
Joined: Sat Jul 20, 2019 12:16 am

### Re: Catalysts and Rates

Catalysts help speed up reactions though.

chari_maya 3B
Posts: 108
Joined: Sat Sep 07, 2019 12:18 am

### Re: Catalysts and Rates

Question 7.17E asks whether a catalyst accelerating the third step of a three step reaction would increase the overall rate of reaction. Why is the answer no?

KSong_1J
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

### Re: Catalysts and Rates

chari_maya 3B wrote:Question 7.17E asks whether a catalyst accelerating the third step of a three step reaction would increase the overall rate of reaction. Why is the answer no?

I think the answer is no because the rate of the overall reaction depends on the slowest step of the reaction and the third step is the fastest, so the addition of a catalyst shouldn't affect the overall reaction.