## pseudo rate laws

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

Samantha Pacheco 2K
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

### pseudo rate laws

What exactly is a pseudo rate law and when would we use it?

Brevin Hensley 1C
Posts: 24
Joined: Fri Sep 28, 2018 12:25 am

### Re: pseudo rate laws

See Topic 7B in the 7th edition of the textbook. You would use it when rate laws depend on the concentration of more that one species. Take for example,
$Rate of consumption of I^{-}=k_{r}[S_{2}O_{8} \^{2-}][I^{-}]$
Since the persulfate concentration will is nearly the same at the end of the reaction as it was at the beginning of the reaction. You would treat the persulfate concentration as another constant. You now have
$Rate of consumption of I^{-}=k_{r^}^{'}[I^{-}]$

megan blatt 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:28 am

### Re: pseudo rate laws

A psuedo rate law is when a higher rate law is adjusted to essentially form a lower order rate law. This is done in order to see how a single reactant affects the rate and is done by increasing the concentration of one of the reactants so much that any change in it has no effect on the rate.

IsabelLight2H
Posts: 34
Joined: Wed Oct 03, 2018 12:15 am

### Re: pseudo rate laws

How do you know the overall order for a pseudo reaction?

Alondra Olmos 4C
Posts: 32
Joined: Fri Sep 28, 2018 12:21 am

### Re: pseudo rate laws

The overall order of the pseudo-reaction is dependent on the order of the species with the highest concentration.