Units

Jessica Chen 2C
Posts: 103
Joined: Thu Jul 11, 2019 12:17 am

Units

I just want to confirm because I was a bit confused: the units for rate are always the same, but units for rate constants can change depending on the order of the reaction?

Sanjana Munagala_1j
Posts: 103
Joined: Sat Aug 24, 2019 12:17 am
Been upvoted: 1 time

Re: Units

That is correct. The units of rate will always be concentration over time and the rate constant will differ based on the order so that units align on both sides of the equation.

Hope that helps!

005391550
Posts: 103
Joined: Thu Jul 25, 2019 12:15 am

Re: Units

the units for rate will always be M/s while rate constant can be M/w (0 order), 1/s (first order), or 1/Ms (second order)

BNgo_2L
Posts: 95
Joined: Wed Sep 11, 2019 12:17 am

Re: Units

You can determine the unit of the rate constants for each order reaction by using the rate laws to derive k.
(ex. second-order: mol/L s = k [mol/L][mol/L] --> k = L/mol s)

Rebekah Alfred 1J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am
Been upvoted: 1 time

Re: Units

As this visual shows, the units for the rate constant change, but the units for the rate remain the same.

Leonardo Le Merle 1D
Posts: 56
Joined: Wed Feb 27, 2019 12:16 am

Re: Units

The above post also applies for third order reactions; M would be squared in the denominator.

Tanmay Singhal 1H
Posts: 143
Joined: Sat Jul 20, 2019 12:16 am

Re: Units

yes. a good way to determine it is one of the first homework problems in 7A

Jasmine W 1K
Posts: 49
Joined: Sat Sep 07, 2019 12:18 am

Re: Units

yes. the units for rate is always concentration (M) over time (s)

Juliana Chopelas 1A
Posts: 50
Joined: Sat Aug 24, 2019 12:16 am

Re: Units

the units for rate constant will change depending on the order of the reaction but the units for rate is the same