Acids, equilibrium & kinetics · SL/HL
Equilibrium Constant / Reaction Quotient Calculator
Enter one term per line as “concentration exponent”. Omit pure solids and liquids when the equilibrium expression requires it.
Your values
Start with the example or enter your own values. Use a dot for decimals and e for scientific notation.
Calculated locally. No account or input upload.
Result & working
ExampleThe calculator is loading. The worked example is also shown below.
Step-by-step working
The formula
K or Q = product of product-side activities/concentrations raised to coefficients divided by the corresponding reactant-side product
| Symbol | Meaning |
|---|---|
| exponent | Stoichiometric exponent in the chosen concentration expression. |
When to use this calculator
The numerical expression must match the equilibrium and convention specified in the problem. This generic tool evaluates the expression you enter; it does not decide which species belong in it.
Worked example
The page opens with these example values. The result below is pre-generated for reference.
- Numerator term: (0.8)^(2) = 0.64
- Numerator term: (0.4)^(1) = 0.4
- Denominator term: (0.2)^(1) = 0.2
- Denominator term: (0.5)^(1) = 0.5
- Q = 0.256 / 0.1 = 2.56
Q = 2.56
Common mistakes
- Do not include pure solids or pure liquids in expressions where their activity is taken as unity.
- Use equilibrium concentrations for K; otherwise the same form evaluates Q.