## Unique rates

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

Posts: 91
Joined: Fri Sep 28, 2018 12:16 am

### Unique rates

Even though a unique rate is the same for all concentrations of products of reactants, does it still change with time. Therefore can a unique rate at the beginning of the reaction be different than the unique rate at the end since it is a function of time?

michelle
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

### Re: Unique rates

Yes. Unique rate is spontaneous rate, which will definitely change with time. But we usually talk about the initial rate.

Parth Mungra
Posts: 72
Joined: Fri Sep 28, 2018 12:28 am

### Re: Unique rates

To build off that, we talk about the initial rate of the reactants going to the products only, and not the reverse reaction. This makes our analysis and our calculations nicer.

105169446
Posts: 32
Joined: Fri Sep 28, 2018 12:16 am

### Re: Unique rates

Yes, because the unique rate is an instantaneous rate which means it is different at each point in time.

Alyssa Wilson 2A
Posts: 65
Joined: Fri Sep 28, 2018 12:18 am

### Re: Unique rates

How do you know when to solve for a unique rate, rather than just a normal instantaneous rate? Is it when there is only one [R] and one [P] on either side of the reaction?

Katie_Duong_1D
Posts: 69
Joined: Fri Sep 28, 2018 12:27 am

### Re: Unique rates

A unique rate is the rate of appearance/disappearance of a chemical species, divided by the stoichiometric coefficients. The unique rate changes over time as the reaction continues.