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Catalysts and Rates

Posted: Tue Mar 10, 2020 12:53 am
by alicechien_4F
How come catalysts don't have an effect on the rate of the overall reaction if it lowers the activation energy?

Re: Catalysts and Rates

Posted: Tue Mar 10, 2020 9:08 am
by Shail Avasthi 2C
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.

Re: Catalysts and Rates

Posted: Tue Mar 10, 2020 10:00 am
by PranaviKolla2B
Do we need to know what examples of common catalysts are?

Re: Catalysts and Rates

Posted: Tue Mar 10, 2020 10:39 am
by Vincent Leong 2B
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.

Re: Catalysts and Rates

Posted: Tue Mar 10, 2020 10:41 am
by John Liang 2I
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

Re: Catalysts and Rates

Posted: Tue Mar 10, 2020 2:18 pm
by lauraxie2e
They do have an effect on reactions.

Re: Catalysts and Rates

Posted: Thu Mar 12, 2020 2:25 pm
by rohun2H
Catalyst will increase the rate of forwarding reaction by lowering activation energy.

Re: Catalysts and Rates

Posted: Thu Mar 12, 2020 3:12 pm
by Alfred Barrion 2H
Catalysts help speed up reactions though.

Re: Catalysts and Rates

Posted: Thu Mar 12, 2020 7:30 pm
by chari_maya 3B
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?

Re: Catalysts and Rates

Posted: Thu Mar 12, 2020 7:37 pm
by KSong_1J
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.

Re: Catalysts and Rates

Posted: Fri Mar 13, 2020 6:56 pm
by Madelyn Romberg 1H
They do effect the rate of the reactions but to not effect the equilibrium constants.