Chemical Equilibrium Calculator
Compute equilibrium concentrations using the ICE table method for simple chemical reactions. Enter the initial concentration and equilibrium constant to find how far the reaction proceeds.
About this calculator
The ICE (Initial, Change, Equilibrium) table method tracks how concentrations shift from initial conditions to equilibrium. For a simple reaction A ⇌ products with equilibrium constant Kc, the equilibrium concentration of products relative to A can be derived by solving a quadratic or, for small Kc, approximated. The formula used here is: [product] = C₀ × √(Kc × reactionType) / (1 + √(Kc × reactionType)), where C₀ is the initial concentration and reactionType is a numerical factor encoding the reaction stoichiometry. This expression represents a normalized equilibrium extent: it gives the fraction of initial concentration converted at equilibrium. A Kc >> 1 indicates the reaction lies far to the right (products favored), while Kc << 1 indicates reactants are favored. Temperature affects Kc through the van't Hoff equation.
How to use
Suppose an initial concentration [A]₀ = 0.50 M, Kc = 4.0, and reactionType = 1. Step 1: compute √(Kc × reactionType) = √(4.0 × 1) = √4 = 2.0. Step 2: equilibrium concentration = 0.50 × 2.0 / (1 + 2.0) = 0.50 × 2.0 / 3.0 = 1.0 / 3.0 = 0.333 M. The equilibrium concentration of the product is approximately 0.333 M, meaning two-thirds of the initial amount has been converted at equilibrium. Adjust Kc to see how a stronger equilibrium constant drives more product formation.
Frequently asked questions
How do I set up an ICE table for a chemical equilibrium problem?
An ICE table has three rows — Initial, Change, and Equilibrium — and one column per species in the reaction. Write the initial concentrations in the first row (often 0 for pure products). In the Change row, express shifts in terms of a variable x, with reactants losing x (times stoichiometric coefficient) and products gaining x. The Equilibrium row is Initial + Change. Substitute the equilibrium row expressions into the Kc expression and solve for x to find all equilibrium concentrations.
What does a large equilibrium constant Kc mean for a chemical reaction?
A large Kc (much greater than 1) means the reaction strongly favors products at equilibrium — nearly all reactants are converted. A small Kc (much less than 1) means the equilibrium lies to the left and only tiny amounts of product form. Kc = 1 means reactants and products are present in comparable amounts. Kc is temperature-dependent: for exothermic reactions, raising temperature decreases Kc, shifting equilibrium back toward reactants, as described by Le Chatelier's principle.
Why does temperature affect the equilibrium constant in chemical reactions?
The equilibrium constant Kc is related to the standard Gibbs free energy change by ΔG° = −RT ln Kc, and ΔG° itself depends on temperature through ΔG° = ΔH° − TΔS°. As temperature changes, ΔG° changes, so Kc changes. For endothermic reactions (ΔH° > 0), increasing temperature raises Kc and favors products. For exothermic reactions (ΔH° < 0), increasing temperature lowers Kc and favors reactants. This is the thermodynamic basis of Le Chatelier's principle and is quantified by the van't Hoff equation.