## Determining Rate Orders

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

Emily Ng_4C
Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

### Determining Rate Orders

How can you tell what the order of each reactant is based on a table of rates and concentrations? Is there a formula or pattern?

Mya Majewski 1L
Posts: 89
Joined: Fri Sep 25, 2015 3:00 am

### Re: Determining Rate Orders

You look at when one reactant changes and the other doesn't or stays the same (lets say the one reactant doubles). Then, you compare this to the corresponding reaction rate and if that changes (lets say it doubles for instance).
So, you will be left with 2^x (2 raised to the X equals the rate)=2 (rate doubled)
x=1, therefore, that specific reactant is first order.
Repeat again for other reactant when its concentration changes and use the experiments when the other reactant (the one you just calculated) stays the same.

Kobe_Wright
Posts: 83
Joined: Fri Sep 28, 2018 12:16 am

### Re: Determining Rate Orders

There's good examples of this in this weeks worksheets posted by a UA

Sophie Roberts 1E
Posts: 61
Joined: Fri Sep 28, 2018 12:17 am

### Re: Determining Rate Orders

You look at when the concentration of one reactant changes and the amount their corresponding reaction rates change. You then raise the concentration to the power "n" and set it equal to the change in reaction rates to find the exponents of the reactants in the rate law. Once you find the exponents of all the reactants, you can determine the order of the reaction.