Unit for reaction rates

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

Diviya Khullar 1G
Posts: 59
Joined: Fri Sep 28, 2018 12:19 am

Unit for reaction rates

When calculating the rate of a reaction, will the units include time? For example, will it be L$L\cdot mol^{-1}\cdot s^{-1} or L\cdot mol^{-1}$

Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: Unit for reaction rates

The unit will include time because the rate of a reaction is measured in M/s or mol*L-1*s-1

MaanasO 1A
Posts: 72
Joined: Fri Sep 28, 2018 12:26 am

Re: Unit for reaction rates

The reaction rate is based on change in M w/ respect to time, so you'll need M/s as the final units.

taline_n
Posts: 64
Joined: Fri Sep 28, 2018 12:17 am

Re: Unit for reaction rates

The rate of the reaction will always be in terms of mol/L•s, but the units for k changes based on the overall order of the reaction. If order=1, the unit for k is s^-1. If order=2, the unit for k is L/mol•s. If order=3, the unit for k is L^2/mol^2•s.

Lorena Zhang 4E
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

Re: Unit for reaction rates

The final rate would always be M/s or mol/(L*s). Therefore, if the order of the reaction changes, in order to reach the final unit of M/s, the unit of k will have to change.