1. A reaction reaches equilibrium

3. Solids and liquids never appear in equilibrium expressions
P4 (s) + 6Cl2 (g) ⇌ 4PCl3 (l)
Keq =
[Cl2]6
By convention, the constant concentrations of pure solids and liquids are understood to be incorporated into the equilibrium constant itself and left out of the equilibrium constant expression.

4. P4 (s) + 6Cl2 (g) ⇌ 4PCl3 (l)

5. The composition of equilibrium mixture is independent of amount of solid present, as long as some is always present.

6. Q < K Reaction shifts right to form more products.
Reaction Quotient
Increasing Q
(reactants only)
Q = ∞
Keq
Q = 0
(products only)
Q < K Reaction shifts right to form more products.
Q = K System is at equilibrium.
Q > K Reaction shits left to form more reactants.