Equilibrium Constant Calculator
⚖ Acids, Bases & Equilibrium. Use the Equilibrium constant formula to find kc, [a], a, [b], b, [c], c, [d], d: pick the value you want, type the others, and the answer updates as you go.
For aA + bB ⇌ cC + dD. Default: N₂ + 3H₂ ⇌ 2NH₃.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Kc | no unit |
| [A] | mol/L |
| a | no unit |
| [B] | mol/L |
| b | no unit |
| [C] | mol/L |
| c | no unit |
| [D] | mol/L |
| d | no unit |
Worked example
Find the kc when [A] = 1 mol/L, a = 1, [B] = 2 mol/L, b = 3, [C] = 2 mol/L, c = 2, [D] = 1 mol/L, d = 0.
Using Kc = [C]^c[D]^d/[A]^a[B]^b: Kc = 0.5.
Frequently asked questions
What is the formula for Equilibrium constant?
Kc = [C]^c[D]^d/[A]^a[B]^b. For aA + bB ⇌ cC + dD. Default: N₂ + 3H₂ ⇌ 2NH₃.
What do the letters stand for, and what units are used?
Kc, [A] in mol/L, a, [B] in mol/L, b, [C] in mol/L, c, [D] in mol/L, d.
How do you calculate kc?
Put the values into Kc = [C]^c[D]^d/[A]^a[B]^b. For example, with [A] = 1 mol/L, a = 1, [B] = 2 mol/L, b = 3, [C] = 2 mol/L, c = 2, [D] = 1 mol/L, d = 0, kc = 0.5.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (kc, [a], a, [b], b, [c], c, [d], d) and fill in the others: it rearranges the formula for you.
