What does K_c tell you?
Which side a reversible reaction favours at balance. Big K_c = mostly products; small K_c = mostly reactants; near 1 = a real mix. It is a single number for the position of equilibrium.
// chemistry › Equilibrium
Equilibrium Constant (K_c)
Calculate K_c = [Products]/[Reactants], with symbol legend and real-world examples.
Kᴄ = \frac{[\text{Products}]}{[\text{Reactants}]}
Frequently asked questions
Does adding more reactant change K_c?
No - K_c is fixed at a given temperature. Add reactant and the system makes more product to restore the same ratio. Only temperature changes K_c itself.
Where is it used in industry?
Optimising reactions like the Haber process for ammonia - choosing conditions that push K_c toward the product you want, to maximise yield.
Why are pure solids and liquids left out?
Their concentration does not change, so they are folded into K_c. Only gases and dissolved species, whose concentrations vary, appear in the expression.
How does K_c relate to Q?
Q is the same ratio at any moment. If Q < K_c the reaction goes forward; if Q > K_c it goes backward; if equal, it is at equilibrium.