Le Chatelier's Principle Calculator

When a chemical reaction at equilibrium is disturbed — by changing concentration, temperature, or pressure — Le Chatelier's Principle predicts which direction the reaction will shift to restore balance. Enter your balanced chemical equation (with phase labels), select whether the reaction is exothermic or endothermic, then choose the type of stress applied to get the equilibrium shift direction, the chemical reasoning behind it, and the effect on products and reactants.

Include phase labels: (g) gas, (l) liquid, (s) solid, (aq) aqueous

Reaction Enthalpy *

Specify which species and whether increased/decreased/added/removed

Results

Equilibrium Shift Direction

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Reasoning

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Effect on Products/Reactants

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Frequently Asked Questions

What is Le Chatelier's principle?

Le Chatelier's principle states that when a system at equilibrium is subjected to a change in concentration, temperature, pressure, or other factors, the equilibrium will shift in the direction that counteracts the imposed change to restore equilibrium.

How does temperature change affect chemical equilibrium?

For exothermic reactions, increasing temperature shifts equilibrium toward reactants (left), while decreasing temperature favors products (right). For endothermic reactions, the opposite occurs - higher temperature favors products, lower temperature favors reactants.

What happens when you increase the concentration of a reactant?

According to Le Chatelier's principle, increasing the concentration of a reactant will shift the equilibrium toward the products (right) to consume the excess reactant and restore equilibrium.

How does pressure change affect gaseous equilibria?

Increasing pressure (decreasing volume) shifts equilibrium toward the side with fewer gas molecules. Decreasing pressure (increasing volume) favors the side with more gas molecules. This only applies to reactions involving gases.

Do catalysts affect the position of equilibrium?

No, catalysts do not change the equilibrium position. They only increase the rate at which equilibrium is reached by lowering the activation energy for both forward and reverse reactions equally.

What is the effect of adding an inert gas to an equilibrium system?

Adding an inert gas at constant volume has no effect on equilibrium position because it doesn't change the partial pressures of the reacting species. At constant pressure, it effectively decreases the pressure of reacting gases, shifting equilibrium toward more gas molecules.

How do you predict equilibrium shifts for concentration changes?

Use Le Chatelier's principle: if you increase a substance's concentration, equilibrium shifts away from that substance. If you decrease a concentration, equilibrium shifts toward that substance to replace what was removed.

Why is phase information important in equilibrium calculations?

Phase labels (g), (l), (s), (aq) are crucial because Le Chatelier's principle applies differently to different phases. For example, pressure changes only affect gaseous species, and pure solids/liquids don't appear in equilibrium expressions.