## what if

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

inlovewithchemistry
Posts: 104
Joined: Fri Sep 28, 2018 12:19 am

### what if

what would the overall rate for the reaction H2 + I2 --> 2HI look like if it was first order?

i know that the second order formula is rate = k[H2][I2], but dont know what to give if it asked for first order.

Mahir_Hasan2C
Posts: 60
Joined: Fri Sep 28, 2018 12:25 am

### Re: what if

It will still be second order since each reactant is first order.

Chem_Mod
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### Re: what if

For each given reaction, there would be only one unique rate law. Thus, the rate law of a reaction cannot sometimes be first order, sometimes second order. In addition, you cannot determine directly from the written reaction what order it is. It can only be determined by experiment.

Charles Hood Disc 1C
Posts: 39
Joined: Fri Sep 28, 2018 12:19 am

### Re: what if

You can't just make it first order. The order of a reaction is determined empirically and cannot be changed. However, if you had a reaction that was simply first order the rate law would appear as Rate = k[A]. Also, a second order rate law is rate = k[A]2.