Molarity Calculator
How It Works
Molarity (M) is the most common unit of concentration in chemistry. It measures the number of moles of solute dissolved per liter of solution. The formula is straightforward: M = n / V, where n is moles of solute and V is volume in liters.
A 1 M solution contains 1 mole of solute per liter. To prepare a 1 M NaCl solution, you would dissolve 58.44 g (the molar mass of NaCl) in enough water to make 1 liter of total solution. Note that you add solute first and then add solvent to reach the target volume.
Molarity is temperature-dependent because solution volume changes with temperature. For precise work, specify the temperature. Molality (moles per kilogram of solvent) is temperature-independent and preferred for colligative property calculations.
Frequently Asked Questions
What is the difference between molarity and molality?
Molarity (M) is moles of solute per liter of solution. Molality (m) is moles of solute per kilogram of solvent. Molality is temperature-independent because mass does not change with temperature, unlike volume.
How do I convert molarity to grams per liter?
Multiply molarity by the molar mass (molecular weight) of the solute. For example, 0.5 M NaCl = 0.5 × 58.44 = 29.22 g/L.
What does a 1M solution mean?
A 1M (one molar) solution contains exactly 1 mole of solute dissolved in enough solvent to make 1 liter of total solution. This is a common stock concentration in chemistry labs.
Can molarity be greater than 1?
Yes, concentrated solutions can have molarities well above 1 M. Concentrated hydrochloric acid is about 12 M, and concentrated sulfuric acid is about 18 M.