## Rate Law and Order

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

Siddiq 1E
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

### Rate Law and Order

Can someone explain the relationship between rate law, order, and molecularity?

405318478
Posts: 90
Joined: Sat Jul 20, 2019 12:16 am

### Re: Rate Law and Order

the rate law tells you the overall rate of the reaction in terms of its reactants, this will include K. the rate order depends on the exponent on each reactant, which indicates the number of molecules of that substance that needs to collide. Molecularity refers to the number of species in an elementary step. The rate law of each elementary step follows directly from molecularity.

Hope this helps!

Siddiq 1E
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

### Re: Rate Law and Order

405318478 wrote:the rate law tells you the overall rate of the reaction in terms of its reactants, this will include K. the rate order depends on the exponent on each reactant, which indicates the number of molecules of that substance that needs to collide. Molecularity refers to the number of species in an elementary step. The rate law of each elementary step follows directly from molecularity.

Hope this helps!

Thanks, I understand more the relationship between rate law and molecularity but I'm still confused about rate order and molecularity. Does molecularity determine rate order or vice versa or not?