For the reaction cu2s(s) ⇌ 2cu+(aq) + s2- (aq), the equilibrium concentrations are as follows: [cu+ ] = 1.0 × 10-5 m, [s2-] = 1.0 × 10-2 m. the equilibrium constant is:

1.0 x 10⁻¹².

Explanation:

Cu₂S(s) ⇌ 2Cu⁺(aq) + S²⁻(aq),

The equilibrium constant (Keq) = [Cu⁺]²[S²⁻]/[Cu₂S].

[Cu⁺] = 1.0 × 10⁻⁵ M, [S²⁻] = 1.0 × 10⁻² M.

[Cu₂S] = 1.0, since the concentration of solid is always can be considered = 1.0.

∴ Keq = [Cu⁺][S²⁻]/[Cu₂S] = (1.0 × 10⁻⁵)²(1.0 × 10⁻²)/(1.0) = 1.0 x 10⁻¹².

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >