Chemistry
Molarity from moles and volume
The defining relation. Divide moles of solute by litres of solution — the volume measured after dissolving, not the solvent added.
The Formula
M = n / V
The defining relation. Divide moles of solute by litres of solution — the volume measured after dissolving, not the solvent added.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| M | Molarity | mol/L | Moles of solute per litre of solution; the standard concentration unit. |
| n | Amount of solute | moles | In moles. Convert from a weighed mass by dividing by molar mass. |
| V | Volume of solution | litres | In litres, measured after the solute has dissolved. |
What Each Symbol Means
Mmol/L
Molarity
Moles of solute per litre of solution; the standard concentration unit.
nmoles
Amount of solute
In moles. Convert from a weighed mass by dividing by molar mass.
Vlitres
Volume of solution
In litres, measured after the solute has dissolved.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate molarity page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Molarity, filed under Science. Every number the guide produces comes from substituting into this one line.