# Equilibrium Constant

Calculator of the equilibrium constant of a chemical reaction.

Chemical reaction :
$$\ce{aA + bB <=> cC + dD}$$ where molecules A,B,C,D are the reactants and products of the reaction and a,b,c,d are the coefficients of molecules A, B, C, D.

Equilibrium constant formula : K_c = \frac{[C]^c*[D]^d}{[A]^a*[B]^b} [A], [B], [C], [D] are the concentrations of A, B, C and D in mol per liter.

Do not enter molecules symbols like SO2, H2 ... Enter data separated by space(s).
Powers of 10 : input 2.5*10^-3 or 2.5e-3 for [A] = 2.5*10^(-3) mol/l

input [A] [B] ... (spaces separated)
input [C] [D] ... (spaces separated)
a b ... (spaces separated)
c d ... (spaces separated)

This tool calculates the equilibrium constant for a chemical reaction.

We consider the following chemical reaction :
$$\ce{aA + bB <=> cC + dD}$$

A and B are the reactants.
C and D are the products.
a and b are the reactant coefficients.
c and d are the product coefficients.

The equilibrium constant is calculated as follows,
K_c = \frac{[C]^c*[D]^d}{[A]^a*[B]^b}

[A]: Molar concentration of reactant A in mol per liter (mol/l)
[B]: Molar concentration of reactant B in mol per liter (mol/l)
[C]: Molar concentration of product C in mol per liter (mol/l)
[D]: Molar concentration of product D in mol per liter (mol/l)

Example of use

This is the chemical reaction of ammonia synthesis:
$$\ce{N2 + 3H2 <=> 2NH3}$$

There are 2 reactants which are nitrogen and hydrogen and one product, ammonia.

Reactants:
A = N_2
B = H_2

The product:
C = NH_3

Coefficients:
a = 1
b = 3
c = 2

Then, the following values should be entered in the form:
- Field "Coefficients of Reactants" : 1 3
- Field "Coefficients of Products" : 2

If we suppose the equilibrium molar concentrations are (in mol/l):
[N_2] = 0.03
[H_2] = 0.09
[NH_3] = 1.7*10^(-8)

Then, we should enter the following values in the calculator:
- Field "Reactant concentrations (mol/l)": 0.03 0.09
- Field "Product concentrations (mol/l)": 1.7e-8

That leads to the following calculator: Kc = 1.32*10^(-11)