chemistry ques- rate law problem

[SerineProtease]

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Hey does anyone know how to find the rate order with respect to a certain reactant when more than one reactant is changing at a time? Here's an example

Trial A B rate
1 1 1 1
2 2 1 2
3 4 3 36

Whats the rate order with respect to B?

I know the answer...i just dont know why....and how.....

Thanks....I'm taking the DAT sometime this August...any suggestions??? other than do really well? (hopefully).....

 

[Three-Oh]

Hey does anyone know how to find the rate order with respect to a certain reactant when more than one reactant is changing at a time? Here's an example

Trial A B rate
1 1 1 1
2 2 1 2
3 4 3 36

Whats the rate order with respect to B?

I know the answer...i just dont know why....and how.....

Thanks....I'm taking the DAT sometime this August...any suggestions??? other than do really well? (hopefully).....

you probably only do it the short way - but you'll need simultaneous equations here! i think! calc those x's and y's here!

 

[SunnyD0119]

im confused w/ this question too...i don't knwo how to do it at all...i can do the regular rate law q's when they are constant can anyone explain this one??
thanks

 

[dat_student]

Hey does anyone know how to find the rate order with respect to a certain reactant when more than one reactant is changing at a time? Here's an example

Trial A B rate
1 1 1 1
2 2 1 2
3 4 3 36

Whats the rate order with respect to B?

I know the answer...i just dont know why....and how.....

Thanks....I'm taking the DAT sometime this August...any suggestions??? other than do really well? (hopefully).....

Isn't it k[A]^2 (i.e. 2nd order w/ respect to B)?

 

[Smooth Operater]

I don't think it's possible to calculate this problem with the info. given. Don't you need at least two concentration of A to be equivalent in order to solve for the order in respect to B ?

 

[dat_student]

I don't think it's possible to calculate this problem with the info. given. Don't you need at least two concentration of A to be equivalent in order to solve for the order in respect to B ?

No, I could come up with an answer (please, see my other post)

 

[sailinx]

Hey does anyone know how to find the rate order with respect to a certain reactant when more than one reactant is changing at a time? Here's an example

Trial A B rate
1 1 1 1
2 2 1 2
3 4 3 36

Whats the rate order with respect to B?

I know the answer...i just dont know why....and how.....

Thanks....I'm taking the DAT sometime this August...any suggestions??? other than do really well? (hopefully).....

From Trial 1 and 2, you can get the order for A (=1). And then create the following 2 equations from trial 2 and 3 (you can pick 1 and 3 also):
Let say rate is represented by:
rate = k [A]^y

From Trial 2:
2 = k[2][1]^y ---- (I)

from Trial 3:
36 = k[4][3]^y -----(II)

Divide (II) by (I), you will get

36/2 = [4][3]^y/[2][1]^y
y = 2.

Therefore, order for B is 2.

🙂