What can this Ksp & precipitation calculator do?

It helps you relate the solubility product Ksp, molar solubility and ion concentrations, test whether a precipitate will form when two ionic solutions are mixed (Q vs Ksp), and sketch which of two salts precipitates first in a simple fractional precipitation scenario.

Which simplifications does it use?

Activities are approximated by molar concentrations and temperature effects on Ksp are not modeled; the focus is on classroom-style examples with clear stoichiometry. For common-ion and precipitation problems, the calculator uses straightforward numeric solvers while keeping all equilibrium concentrations non-negative.

Solubility product (Ksp) & precipitation calculator

How to use (3 steps)

Pick a mode: Ksp → solubility, solubility → Ksp, Q vs Ksp (precipitation test), or simple fractional precipitation.
Enter the salt, stoichiometric coefficients, Ksp or solubility, and concentrations or volumes as needed.
Compute to see solubility, Ksp, Q vs Ksp, and interval summaries. Copy the URL to share the exact setup.

Default examples use classic salts such as AgCl and CaF2 so that you can see results immediately and compare with textbook values.

Inputs

Choose a mode, adjust the example values, then compute or copy the URL. Units use mol/L and g/L for clarity.

Ksp → solubility Solubility → Ksp Precipitation test (Q vs Ksp) Fractional precipitation (simple)

Salt label

Cation coefficient ν_cation

Anion coefficient ν_anion

Molar mass of salt (g/mol, optional)

Ksp

Common anion [A⁻]₀ (mol/L, optional)

If you enter a common anion concentration (e.g. NaCl already present), the calculator solves the Ksp expression numerically for the new molar solubility.

Results

Mode: Ksp → solubility

How it is calculated

Steps will appear here after calculation.

FAQ

Does this tool account for activities and ionic strength?

For simplicity, it treats activities as equal to molar concentrations and does not include activity coefficients or ionic-strength corrections. It is meant for teaching-level Ksp and precipitation exercises, not for precise analytical calculations.

Which salts and stoichiometries can I use?

The core formulas accept general ν_cation and ν_anion coefficients (for example 1:2 salts such as CaF₂), as long as you provide the correct stoichiometric coefficients and Ksp values. For fractional precipitation, the built-in explanation assumes simple 1:1 salts with a shared anion.

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