Help! Kinetics and the Rate of Formation???

For the following reaction, write expressions for the rate of formation of each of the products.
3 A + 2 B + 2 C → D + 3 E + 4 F

1 Answer
Feb 4, 2018

Well, by definition, D has the rate of reaction. It's a product, with a coefficient of 1.

r(t) = +1/1(Delta[D])/(Deltat)

How do we suppose we equalize all the rates? In forward reactions, reactants cannot appear. Products cannot disappear.

So some human intervention is necessary... aka, normalization.

There are color(red)(3) A and color(red)(2) C reactants, and color(red)(4) F products for every 1 D product. Thus,

overbrace(color(red)(-)1/color(red)(3)(Delta[A])/(Deltat) = [ . . . ] = color(red)(-)1/color(red)(2)(Delta[C])/(Deltat))^("reactants") = overbrace(+1/color(red)(1)(Delta[D])/(Deltat) = [ . . . ] = +1/color(red)(4)(Delta[F])/(Deltat) )^"products" = r(t)

And with that, A, which disappears three times as fast as D appears, now is scaled such that it equals the rate of reaction. So how is this done for the rest of the substances in solution?