How to use the reaction quotient and direction calculator
Find the reaction quotient for A + B ⇌ C and which way the reaction will shift. Enter concentration of a, concentration of b, concentration of c, equilibrium constant in the fields above; the reaction quotient q, predicted direction are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “reaction quotient Q”, “Le Chatelier direction”, “equilibrium shift prediction”, “calculate reaction quotient and direction”, “find reaction quotient q”.
Formula
Variables
- A — Concentration of A (M)
- B — Concentration of B (M)
- C — Concentration of C (M)
- Kc — Equilibrium constant
Worked example
With concentration of a = 0.2 M, concentration of b = 0.5 M, concentration of c = 0.1 M, equilibrium constant = 4, the calculator gives reaction quotient q ≈ 1; predicted direction ≈ Shifts toward products.
Frequently asked questions
What is the reaction quotient and direction calculator used for?
Find the reaction quotient for A + B ⇌ C and which way the reaction will shift. It helps with questions such as “reaction quotient Q”, “Le Chatelier direction”, “equilibrium shift prediction”.
What is the formula for the reaction quotient and direction calculation?
Reaction quotient Q = C / (A × B). Predicted direction = C / (A × B)<Kc?"Shifts toward products":"Shifts toward reactants". Here A is concentration of a (M), B is concentration of b (M), C is concentration of c (M), Kc is equilibrium constant.
What inputs do I need for the reaction quotient and direction calculator?
You need concentration of a in M, concentration of b in M, concentration of c in M, equilibrium constant. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the reaction quotient and direction calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the reaction quotient and direction result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.