Ionic Strength Calculator

Ionic strength (I) measures total ion concentration in solution, weighted by charge squared: I = ½eciz_i squared. For 0.1 M NaCl: I = 0.5x(0.1x1 squared + 0.1x1 squared) = 0.1 M. For 0.1 M CaCl2: I = 0.5x(0.1x2 squared + 0.2x1 squared) = 0.3 M. Higher charge ions contribute more.

Ionic strength affects activity coefficients, solubility, reaction rates, and electrostatic interactions. In the Debye-Huckel equation: log(gamma) = -A|z|sqrt(I). Higher I means ions interact more strongly, reducing their effective concentration for reactions. Essential for accurate equilibrium calculations.

I = ½eciz_i squared for ALL ions present. For 0.1 M Na2SO4: I = 0.5x[0.2x1 squared + 0.1x2 squared] = 0.5x[0.2 + 0.4] = 0.3 M. For seawater (~0.6M total salts): I approx 0.7 M. Always include every ion in the sum.

For 1:1 electrolytes (like NaCl): I = molarity. For 2:1 electrolytes (like CaCl2): I = 3xmolarity. For 2:2 electrolytes (like MgSO4): I = 2xmolarity. For 3:1 electrolytes (like AlCl3): I = 6xmolarity. Multiply by charge product factors.