## Rate = k[A][B] vs rate = -1/a d[A]/dt

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

204635822
Posts: 25
Joined: Fri Sep 25, 2015 3:00 am

### Rate = k[A][B] vs rate = -1/a d[A]/dt

What is the difference between the two equations. Rate = k[A][B] vs rate = -1/a d[A]/dt. I understand that the second one means that reactants go down as reaction progresses because they are used up, but do we ever use that to solve any problems, or is it more of a conceptual thing?

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

### Re: Rate = k[A][B] vs rate = -1/a d[A]/dt

Yes we do use that equation. Just take a look at the practice quiz and the first problem uses those two equations.

Nataliya Karashchuk
Posts: 13
Joined: Fri Oct 02, 2015 3:00 am

### Re: Rate = k[A][B] vs rate = -1/a d[A]/dt

Going off of this, how is Rate=k[A][B] derived from the Rate=-1/a d[A]/dt and is that beyond the scope of this class? I don't really understand the link between the equations