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Molarity Calculator
Molarity Calculator
M = n / V — find molarity, moles, or volume of solution
M (mol/L) = moles (n) / Volume (V, L)
mol
Molarity
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in mmol/L
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in μmol/L
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Moles (n)
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Volume (V)
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Step-by-Step
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About the Molarity Calculator
Molarity is the concentration of a solution in moles of solute per litre of solution. Enter any two values to find the third.
How to use the Molarity Calculator
- Fill in two of Moles of Solute (n), Volume of Solution and Molarity (M), and choose L, mL or ΞΌL for volume.
- Press the matching Find button or Calculate.
Formula and method
M = n Γ· V (V in litres), so n = M Γ V and V = n Γ· M.
Worked example
2 moles of solute in 1 L is 2 M. Also, 0.5 mol in 250 mL (0.25 L) is 0.5 Γ· 0.25 = 2 M.
Making a solution. 58.44 g of sodium chloride (molar mass 58.44 g/mol) dissolved to make 1 L of solution is 1 M.
When to use the Molarity Calculator
- Preparing a solution of a given concentration in a chemistry lab.
- Finding the mass of solute needed for a target molarity.
- Working through concentration problems for a course.
Common mistakes to avoid
- Using the volume of the solvent instead of the final volume of the solution.
- Forgetting to convert millilitres to litres.
Tips
- Convert millilitres to litres before dividing (divide mL by 1,000).
- To find moles from mass, divide the mass by the molar mass.
Frequently Asked Questions
Molarity is moles per litre of solution; molality is moles per kilogram of solvent. Molality does not change with temperature.
Molarity is moles per litre of solution. Molality is moles per kilogram of solvent and does not change with temperature.