Maddz
So Qc is the reaction quotient, it expresses the ratio of reactants to products at a given instant (so you would most likely be given the initial concentration of the reactants and products), however Kc (equilibrium constant) expresses the final concentrations at equilibrium for a reaction.
Both however are calculated using the same formula, Kc and Qc=[products]/[reactants]
What matters is the difference between the values of Qc and Kc.
If:
Qc=Kc the system is at equilibrium
Qc>Kc the system moves to the left or backward reaction
Qc<Kc the system moves to right or forward reaction
Hope this helps, 😀
