Free Reaction Quotient Calculator

Calculate the reaction quotient Q for a reaction aA + bB -> cC + dD to determine reaction direction relative to equilibrium.

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Reaction Quotient (Q)

0.1333

log10(Q)-0.8751

Reaction Quotient (Q) vs Concentration of C [C]

Reaction Quotient (Q)

The reaction quotient has the same mathematical form as the equilibrium constant but is evaluated at non-equilibrium concentrations.

Formula

Q = [C]^c [D]^d / ([A]^a [B]^b)

Compare Q to the equilibrium constant K:

  • If Q < K: reaction proceeds forward (toward products)
  • If Q > K: reaction proceeds in reverse (toward reactants)
  • If Q = K: system is at equilibrium
  • Example Calculation

    For A + B -> C + D with [A]=0.5, [B]=0.3, [C]=0.1, [D]=0.2 M.

    1. 01Q = [C][D] / ([A][B])
    2. 02Q = (0.1 × 0.2) / (0.5 × 0.3)
    3. 03Q = 0.02 / 0.15 = 0.1333

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