order of reaction

Moderators: Chem_Mod, Chem_Admin

Sophia Dinh 1D
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

order of reaction

Postby Sophia Dinh 1D » Sat Mar 14, 2020 6:55 pm

How can you tell what the reaction order is?

WesleyWu_1C
Posts: 117
Joined: Thu Jul 25, 2019 12:16 am

Re: order of reaction

Postby WesleyWu_1C » Sat Mar 14, 2020 7:01 pm

If there are two reactants, the order of a reaction is by adding up the two exponents in the rate law (rate = k[A]^n [B]^M, so the rate law is n + m). How do you find n and m? Usually they give you a bunch of experimental trials where they used different or same amounts of A and B to find different rates. Then you compare the different trials to find out the exponents (which finds the order or reaction) and find the rate constant (k). Dr. Lavelle did at least one practice question in lecture, so you can review that.

VLi_2B
Posts: 99
Joined: Sat Sep 14, 2019 12:15 am

Re: order of reaction

Postby VLi_2B » Sat Mar 14, 2020 7:03 pm

This video is pretty good at explaining the concepts.
https://www.khanacademy.org/science/che ... tion-order

Emily Burghart 1k
Posts: 50
Joined: Wed Sep 18, 2019 12:17 am

Re: order of reaction

Postby Emily Burghart 1k » Sat Mar 14, 2020 8:13 pm

This is a good video! I watched another of his videos on other general kinetics problems, and it was good.

https://www.google.com/url?sa=t&rct=j&q ... M6e6Itn124

BeylemZ-1B
Posts: 95
Joined: Thu Jul 25, 2019 12:17 am

Re: order of reaction

Postby BeylemZ-1B » Sun Mar 15, 2020 4:55 am

You can also think of this graphically. I doubt we will ever be asked to do this by hand on a test, but if you graph the concentration [A]t vs time and you get a straight line, it is zeroth order. If you graph the natural log of the [A]t vs time and get a linear graph, it is first order. if you graph the reciprocal (1/[A]t) vs time and you get a straight line, it is second order.

gconcha
Posts: 37
Joined: Fri Aug 09, 2019 12:16 am
Location: Sunset Village
Contact:

Re: order of reaction

Postby gconcha » Sun Mar 15, 2020 5:18 am

I think the furthest we'll be tested on is the number of reactants.
Zeroth Order:
First Order:
Second Order:
Third Order:

Connor Chappell 2B
Posts: 59
Joined: Wed Feb 20, 2019 12:16 am

Re: order of reaction

Postby Connor Chappell 2B » Sun Mar 15, 2020 5:44 am

Within the scope of this class, we will be asked to find the order of reactions based on experimental data, which is the example with multiple experiments where the concentrations of each reactant varied between each experiment and this resulted in a differing rate of the overall reaction.


Return to “Method of Initial Rates (To Determine n and k)”

Who is online

Users browsing this forum: No registered users and 0 guests