Theory & Formula
Molarity (M) is defined as the number of moles of solute per liter of solution. It is the most common unit of concentration used in chemistry because it allows easy conversion between volume of solution and moles of solute.
C = (m / MW) / V
- C = Molarity (mol/L or M)
- m = Mass of solute (g)
- MW = Molar mass of solute (g/mol)
- V = Volume of solution (L)
Assumptions & Limitations
This calculation assumes ideal behavior and that volumes are additive (which is strictly only true for ideal solutions, but is a standard assumption for introductory bench work). It does not account for volume changes that may occur upon mixing certain solutes and solvents (e.g., ethanol and water). Temperature is assumed to be standard ambient (volumes expand/contract with temperature).