orders


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Ghadir Seder 1G
Posts: 134
Joined: Sat Sep 14, 2019 12:17 am

orders

Postby Ghadir Seder 1G » Tue Mar 10, 2020 3:42 pm

How do I determine the order of the reaction using experimental data such as those in problem 7a.17?

ShravanPatel2B
Posts: 100
Joined: Fri Aug 30, 2019 12:18 am

Re: orders

Postby ShravanPatel2B » Tue Mar 10, 2020 5:23 pm

you would determine overall order by adding up the orders of the individual species in the rate law. in this case it would be 5. A is in first order and B and C are in second order.

Callum Guo 1H
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Re: orders

Postby Callum Guo 1H » Tue Mar 10, 2020 6:16 pm

add up the orders of all of the substances.

VioletKo3F
Posts: 103
Joined: Sat Sep 07, 2019 12:18 am

Re: orders

Postby VioletKo3F » Tue Mar 10, 2020 6:39 pm

You first have to determine the orders of the individual reactants by comparing the reaction rate and concentration. For the reaction order, you would add the orders of the reactants together. For 17, it would be 1 (A) + 2 (B) + 2 (C) = 5.

Jacob Motawakel
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Re: orders

Postby Jacob Motawakel » Tue Mar 10, 2020 7:07 pm

you use the table to find the order of each reactant. To do this, you have to keep all reactants constant at two different experiments, except for the one you want to calculate. Then compare the quotient of the concentration of the reactant you want to calculate to the quotient of the initial reaction rate. And whatever power you have to raise the reactant concentration quotient to in order to equal the quotient of the initial reaction rate is the order for that reactant.

Charlene Datu 2E
Posts: 62
Joined: Wed Sep 11, 2019 12:16 am

Re: orders

Postby Charlene Datu 2E » Tue Mar 10, 2020 10:46 pm

For a problem with three species being consumed, you would keep all but one of the concentrations constant. You would use a ratio of the rates to compare and isolate an exponent that you're solving for. Using 7A.17 as an example, to determine the exponent of species A, you would use experiments 1 and 2

rate = k [A]^x [B]^y [C]^z

(exp 2)/(exp 1)

exp2 = 17.4 = [2.5]^x [1.25]^y [1.25]^z
exp1 = 8.7 = [1.25]^x [1.25]^y [1.25]^z
*Same values are cancelled

(17.4)/(8.7) = (2.5/1.25)^x
2 = 2^x
x = 1

So far, the overall reaction rate would look like rate = k [A]^1 [B]^y [C]^z
You would repeat the same steps to find the exponents of the other reactants. Using these exponents, you would add them up to determine the order.

Michelle Xie 2B
Posts: 99
Joined: Sat Aug 17, 2019 12:18 am

Re: orders

Postby Michelle Xie 2B » Tue Mar 10, 2020 11:36 pm

first determine orders of individual reactants and then add them together for the overall order.


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