## Unique rate of reaction Hw 15.3

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

BrandonCooper2C
Posts: 14
Joined: Fri Sep 25, 2015 3:00 am

### Unique rate of reaction Hw 15.3

Hey Chem community,

I understand that the unique rate is supposed to be the average rate divided by the stoichiometric coefficient of a product or reactant depending on which unique rate you are looking for, but for part c of hw question 15.3 the book solely asks for the unique rate and does not specify which reactant/product to find it for. How do we know which species involved in the reaction the book is referring to?

Thanks.

visesha_2F
Posts: 16
Joined: Fri Sep 25, 2015 3:00 am

### Re: Unique rate of reaction Hw 15.3

The unique rate is something that is calculated for the whole reaction in general, so it does not account for the moles of the reactants or products. For example, if you were given the unique rate, you would determine each reactant's or product's reaction rate based on that unique rate, which is just a rate that does not account for the number of moles.

BrandonCooper2C
Posts: 14
Joined: Fri Sep 25, 2015 3:00 am

### Re: Unique rate of reaction Hw 15.3

Okay, I now understand that, however I do not understand why the solutions manual divides by 2 then. If the unique rate does not depend on moles then why do they use the rate found for reaction of NO2 then divide by 2 when they ask for the unique rate?

Helen Shi 1J
Posts: 78
Joined: Sat Jul 22, 2017 3:00 am

### Re: Unique rate of reaction Hw 15.3

So what is the unique rate of reaction for Hw 15.3 part c? There is no answer in the textbook.

Matthew Lee 3L
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am

### Re: Unique rate of reaction Hw 15.3

I think the solutions manual divides by 2, because it uses the reaction rate for NO2 which has a stoichiometric coefficient of 2.