Question

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

Answer 1

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?