Reaction Quotient Calculator
Calculate Q from current concentrations and compare to K to predict reaction direction.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Reaction Quotient Calculator
Enter the current (not equilibrium) concentrations of products and reactants with their coefficients, plus the known equilibrium constant K. The calculator computes Q and compares it to K to predict which direction the reaction will shift.
About the Reaction Quotient Calculator
The reaction quotient Q has the same mathematical form as the equilibrium constant K, but uses current concentrations instead of equilibrium concentrations. Comparing Q to K predicts the direction a reaction will shift. This is a direct application of Le Chatelier's principle.
Frequently Asked Questions
What is the difference between Q and K?
K is the equilibrium constant at a specific temperature. Q is the reaction quotient calculated from current (non-equilibrium) concentrations. Comparing Q to K tells you which direction the reaction will shift to reach equilibrium.
What happens when Q < K?
When Q < K, the ratio of products to reactants is too low. The reaction will proceed forward (to the right), converting reactants to products, until Q equals K at equilibrium.
What happens when Q > K?
When Q > K, there are too many products relative to equilibrium. The reaction will proceed in reverse (to the left), converting products back to reactants, until Q equals K.