## Rate Law Units

$\frac{d[R]}{dt}=-k[R]; \ln [R]=-kt + \ln [R]_{0}; t_{\frac{1}{2}}=\frac{0.693}{k}$

Nivi Ahlawat 3I
Posts: 24
Joined: Fri Sep 25, 2015 3:00 am

### Rate Law Units

For first-order rate law constants, does the units need to be in s-1 or min-1?
The solutions guide for 15.29 part a lists the rate constant as 0.17min instead of in seconds.
Thank you!

Daniel Minassian 2D
Posts: 33
Joined: Fri Sep 25, 2015 3:00 am

### Re: Rate Law Units

This really depends on what the units given in the problem are and if they ask for any specific units. As long as your units are consistent you can report in the values you like. There is no rule mandating that k always be reported in seconds, though this may or may not be the norm. I would imagine the convention for it would depend on the speed of the reaction. If a reaction you are monitoring takes hours, then I would assume using inverse seconds as the unit may not be the most convenient.