# order of reaction~

#### ippie

##### ippie
10+ Year Member
A reaction was found to have a half life that depended on the initial concentration of the reactant. For this reaction, which one of the following plots might be linear?

a. ln[A] vs. t
b. 1/[A] vs. t
c. both plots are linear.
d. neither plot is linear

#### poc91nc

##### Membership Revoked
Removed
10+ Year Member
7+ Year Member
Well, we know that first order (choice a) is out of the question since it doesn't depend on initial concentration. Remember the equation for a first order process -2.3log(N/N') = kt initial concentrations will cancel out with substitution. Or you can just use 0.7/k = half life. Second order half life does depend on initial rate. I'd go with choice b which is the linear format for a second order reaction.

1/[A] - 1/[A]' = kt

B

#### BodybldgDoc

b? is that the correct answer?

#### poc91nc

##### Membership Revoked
Removed
10+ Year Member
7+ Year Member
use the expression for the second order reaction and solve for the half life to convince yourself. do the same for first order

B

#### BodybldgDoc

use the expression for the second order reaction and solve for the half life to convince yourself. do the same for first order

You are right. I was questioning the OP as to what the correct answer was because I would have guessed b as well.

This thread is more than 14 years old.

Your message may be considered spam for the following reasons: