## Order?

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

Jesse_torres2H
Posts: 41
Joined: Thu Jul 27, 2017 3:00 am

### Order?

How do you determine what order a reaction is?

Chem_Mod
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### Re: Order?

You could use initial rates method where you measure different initial rates with different initial concentrations.

Refer to class notes to determine which plot gives you a straight line graphing concentration vs time.

Use experimental data to solve for the exponents of your reactants. If you have rate=k[A]x[B]y, you solve for x and y and add them together to find the order.

Come to step-up sessions, discussion sections, office hours for more help! Make sure to ask someone from class for lecture notes in case you missed them.

Mitch Mologne 1A
Posts: 74
Joined: Fri Sep 29, 2017 7:04 am

### Re: Order?

To elaborate, essentially if you take two experiments and only change one initial concentration of reactant, you can observe how the rate of the rxn is affected, thus determining the order in respect to the reactant you altered.

Lindsay Kester 2L
Posts: 29
Joined: Thu Jul 27, 2017 3:00 am

### Re: Order?

You could also look at the slow step of a reaction and figure out it's molecularity. If it's A->B, then first order, A+A->B, second order, and so on.