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Rate constant units

Posted: Sun Mar 18, 2018 9:20 am
by Nicole Nikolov 1K
What is a general rule of thumb to figure out the units of the rate constant and the initial rate? I'm having trouble figuring them out once we get past fourth order reactions...

Re: Rate constant units

Posted: Sun Mar 18, 2018 9:43 am
by SPandya1F
for first order, M/s
for second order, 1/s
for third order, 1/Ms
in general:

Re: Rate constant units

Posted: Sun Mar 18, 2018 10:07 am
by Zane Mills 1E
An easier way to think of it is just match up your concentrations and their exponents with the rate (which you know is M/s or mol/L*s)

Re: Rate constant units

Posted: Sun Mar 18, 2018 5:10 pm
by Phillip Tran
write it all out and cancel whatever you can. whats left is your units

Re: Rate constant units

Posted: Sun Mar 18, 2018 11:43 pm
by Sarah Wax 1G
Another thing I do is whatever the order is, the liters and moles will have an exponent one less than the order.

For fourth order, the rate constant = L^3/ mol^3 * S
For third order, the rate constant = L^2/ mol^2 * s
For second order, the rate constant = L / mol * s

Re: Rate constant units

Posted: Sun Mar 18, 2018 11:59 pm
by Jimmy Zhang Dis 1K
In general the constant is M^1-n*time^-1

Re: Rate constant units

Posted: Tue Feb 19, 2019 12:46 pm
by jane_ni_2d
It's helpful to just write all your units out and then see which ones cancel!