## Kr Units for Different Order Reactions

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

J Medina 2I
Posts: 102
Joined: Wed Sep 25, 2019 12:17 am

### Kr Units for Different Order Reactions

What units is Kr in a first order, 2nd order, and 0 order reaction?

Victoria Zheng--2F
Posts: 103
Joined: Fri Aug 09, 2019 12:17 am

### Re: Kr Units for Different Order Reactions

The unit of K for a zero-order reaction is M/s, which is the same as the unit of rate. The unit of K for a first-order reaction is 1/s. The unit of K for a second-order1/M reaction is 1/M*s. The unit of rate is always M/s

Chris Charton 1B
Posts: 69
Joined: Mon Jun 17, 2019 7:23 am

### Re: Kr Units for Different Order Reactions

Because rate is expressed in M/s, you have to adjust the units for k depending on the order.

0 order; units from [concentration (m/l)]^0 is removed, so k's units are M/s
1st order; units from [concentration (m/l)]^1 is present, so k's units are 1/s
2nd order units from [concentration(m/l)]^2 needs to be countered so k's units are l/m*s or 1/Ms

If the reaction was 3rd order, something like k[A]^2[B], then k's units would be l^2/m^2*s or 1/M^2*s

Nathan Rothschild_2D
Posts: 131
Joined: Fri Aug 02, 2019 12:15 am

### Re: Kr Units for Different Order Reactions

will we have to know third order reactions?