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ICE / Q / K / Ksp Equilibrium Solver

Four equilibrium chemistry modes in one tool. Build ICE tables and solve for equilibrium concentrations, compare the reaction quotient Q to K, calculate molar solubility from Ksp with optional common ion, or solve weak acid/base problems for pH and percent ionization.

Presets

ICE Table Setup

Qinitial=0,K=0.00460Q_{\text{initial}} = 0, \quad K = 0.00460→ Shifts right

ICE Table

N2O4⇌2NO2N_{2}O_{4} \rightleftharpoons 2 NO_{2}
N2O4\mathrm{N_{2}O_{4}}NO2\mathrm{NO_{2}}
I0.10000
C-0.01016+0.02033
E0.089840.02033

Step-by-Step Solution

1Write the equilibrium expression
K=[NO2]2[N2O4]=0.00460K = \frac{[\mathrm{NO_{2}}]^{2}}{[\mathrm{N_{2}O_{4}}]} = 0.00460
2Set up ICE table with extent x
[N2O4]e=0.1−x,[NO2]e=0+2x[\mathrm{N_{2}O_{4}}]_e = 0.1 - x, \quad [\mathrm{NO_{2}}]_e = 0 + 2x
3Solve for x
x=0.0102x = 0.0102
4Calculate equilibrium concentrations
[N2O4]=0.0898 M[\mathrm{N_{2}O_{4}}] = 0.0898 \text{ M}
[NO2]=0.0203 M[\mathrm{NO_{2}}] = 0.0203 \text{ M}
5Verify
Kcalc=0.00460≈0.00460K_{\text{calc}} = 0.00460 \approx 0.00460

Reference Guide

ICE Table Method

ICE stands for Initial, Change, Equilibrium. For a reaction aA + bB ⇌ cC + dD, set up a table where the change row uses the variable x multiplied by the stoichiometric coefficient.

K=[C]c[D]d[A]a[B]bK = \frac{[C]^c[D]^d}{[A]^a[B]^b}

Substitute equilibrium expressions into K and solve for x, typically using the quadratic formula.

Reaction Quotient Q

Q has the same form as K but uses current (non-equilibrium) concentrations. Compare Q to K to predict which direction the reaction will shift to reach equilibrium.

Q<K⇒shift rightQ>K⇒shift leftQ < K \Rightarrow \text{shift right} \qquad Q > K \Rightarrow \text{shift left}

Ka and Kb

Ka measures the strength of a weak acid. The ICE table for HA ⇌ H⁺ + A⁻ gives a quadratic that solves for the hydrogen ion concentration, from which pH follows.

Ka=x2C0−xpH=−log⁡10(x)K_a = \frac{x^2}{C_0 - x} \qquad \text{pH} = -\log_{10}(x)

For a weak base, Kb works the same way but yields [OH⁻], and pH = 14 - pOH.

Ksp (Solubility Product)

Ksp describes the equilibrium between a solid ionic compound and its dissolved ions. For AₚBₙ dissolving into m cations and n anions, the molar solubility s satisfies the Ksp expression.

Ksp=(ms)m(ns)nK_{sp} = (ms)^m(ns)^n

Adding a common ion (an ion already present in solution) decreases solubility, as predicted by Le Chatelier's principle.