## First order

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

Gabriela Carrillo 1B
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### First order

When given a chart, would we identify a reactant as being first order if when its molarity is doubled the rate is doubled?

Justin Chu 1G
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Been upvoted: 1 time

### Re: First order

Only if all the other reactants remain constant. Otherwise, you would be unable to tell which change in concentration is affecting the rate and how.

Jiun Yue Chung 2I
Posts: 27
Joined: Fri Sep 29, 2017 7:06 am

### Re: First order

Generally if the concentration of a reactant doubles along with the reation's initial rate, it should be first order reaction. However, always do the arithmetic just to be sure :)

Nora 1F
Posts: 46
Joined: Fri Sep 29, 2017 7:04 am

### Re: First order

Justin is correct! So just to clarify, a reactant is first order if when all other reactant concentrations are held constant and the concentration reactant of interest is doubled, the rate doubles.

Josh Moy 1H
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am

### Re: First order

If the other reactant's concentrations remain constant then yes it would be first order