K constants

[Jasmin Argueta 1K]

In regards to K in chemical kinetics, when would we use big K and little k? are both needed only when using the pre-equilibrium approach? I know big K is products/reactants and little k is forward/reverse or k1/k1'. Is this the only instance we'll need to connect the two? I am asking because I usually make mistakes when using the same varibales so don't particularly favor these problems

[Jonny Schindler 1A]

I think relating big K to the forward and reverse reactions is the only way to connect them.

[Joonsoo Kim 4L]

I think you use big K to convert the concentration of an intermediate in terms of concentrations of species found in the experimentally determined rate law. You can then convert big K into little k's using K=(k/k') to get your rate law all in terms of concentrations and rate constants.