Reaction Quotient Calculator

Calculate Reaction Quotient

Enter Gas Concentrations (M)

About Reaction Quotient

The reaction quotient (Q) is a measure of the relative amounts of products and reactants present during a reaction at a particular point in time.

Q = [Products]^coefficients / [Reactants]^coefficients

For the reaction: aA + bB ⇌ cC + dD

Q = [C]^c × [D]^d / [A]^a × [B]^b

Key relationships:

  • Q < K: Reaction proceeds forward (more products formed)
  • Q = K: Reaction is at equilibrium
  • Q > K: Reaction proceeds reverse (more reactants formed)

Gas Phase:

Use partial pressures or concentrations

Aqueous Solutions:

Use molar concentrations

Heterogeneous Systems:

Pure solids and liquids have activity = 1

The reaction quotient is essential for predicting reaction direction and understanding chemical equilibrium.

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