Reaction quotient
Chemical Equilibrium · Chemistry
Study notes
For N₂ + 3H₂ ⇌ 2NH₃, K_c = 0.5. At some moment [NH₃] = 0.8, [N₂] = 0.2, [H₂] = 0.2 M. Which way? Step 1: Q = (0.8)²/((0.2)(0.2)³) = 0.64/0.0016 = 400. Step 2: Q = 400 > K = 0.5. Step 3: Too much product → shifts LEFT toward reactants. Step 4: As reaction proceeds, Q falls until Q = K — equilibrium. Q is the GPS; K is the address.