What Is the Reaction Quotient (Q) vs Equilibrium Constant (K) Calculator?
The reaction quotient Q measures relative amounts of products and reactants present in a reaction at a specific instant.
How Does the Reaction Quotient (Q) vs Equilibrium Constant (K) Calculator Work?
If Q < K, excess reactants exist, driving the forward reaction. If Q > K, excess products exist, driving the reverse reaction toward equilibrium.
Reaction Quotient (Q) vs Equilibrium Constant (K) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Q = \frac{[C]^c \cdot [D]^d}{[A]^a \cdot [B]^b}, \quad Q < K \implies \text{Right}, \quad Q > K \implies \text{Left}
Reaction quotient Q is product of product concentrations raised to powers over reactant concentrations raised to powers.
How to Use the Reaction Quotient (Q) vs Equilibrium Constant (K) Calculator
- Enter the molar concentrations of reactants and products.
- Enter the stoichiometric coefficients from the balanced equation.
- Input the known equilibrium constant K.
Step-by-Step Example Calculation
Haber Reaction: N₂ + 3H₂ ⇌ 2NH₃
Input Values:
concA:0.5
coeffA:1
concB:0.5
coeffB:3
concC:1.2
coeffC:2
concD:1.0
coeffD:0
equilibriumConstantK:4.3
Worked Steps: With [NH₃]=1.2M, [N₂]=0.5M, [H₂]=0.5M, Q = 23.04 > K = 4.3. The reaction must shift LEFT to produce more reactants.
Understanding Your Result
Reaction Quotient (Q): Calculated mass-action ratio.
Shift Direction: Shift Right (forward), Shift Left (reverse), or Dynamic Equilibrium.
Q/K Ratio: Quantitative distance from equilibrium state.
Factors That Affect the Result
- Concentration changes, vessel compression/dilution, and temperature changes affecting K.
When Should You Use This Calculator?
- Analytical chemistry titration, chemical process engineering, and educational stoichiometry.
Assumptions & Limitations
- Assumes ideal solutions where activity coefficients γ ≈ 1.0. High ionic strengths require activity corrections.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard mass-action law equilibrium model.