StatGardenREF. DESK
Calculators/Chemistry/Kp ↔ Kc equilibrium constant conversion
Chemistry

Kp ↔ Kc equilibrium constant conversion calculator

Convert between pressure-based and concentration-based equilibrium constants for a reaction.

What this calculator does

Kp ↔ Kc equilibrium constant conversion works out convert between pressure-based and concentration-based equilibrium constants for a reaction. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.

The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.

The formula

FormulaKp = Kc·(R·T)^Δn, R = 0.0820574 L·atm/(mol·K), Δn = mol gaseous products − mol gaseous reactants

The inputs explained

FieldWhat to enter
ConvertChoose from Kc → Kp, Kp → Kc.
Known constant (Kc or Kp)A number. Starts at 1.5.
Temperature (K)A number, measured in K. Starts at 298.15.
Δn (mol gas products − mol gas reactants)A number. Starts at 2.

Worked examples

Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.

How the answer changes with known constant (kc or kp)

Every other input is held at the calculator’s starting values while known constant (kc or kp) varies. Select any row to load that scenario into the calculator.

How the answer changes with known constant (kc or kp)
Known constant (Kc or Kp)Kp(R·T)^Δn factorR·T
0.75448.9173547598.556472924.465 L·atm/mol
1.13676.3688144598.556472924.465 L·atm/mol
1.5897.8347093598.556472924.465 L·atm/mol
2.251,346.752064598.556472924.465 L·atm/mol
31,795.669419598.556472924.465 L·atm/mol
4.52,693.504128598.556472924.465 L·atm/mol