How to Calculate Molarity
What is Molarity?
Molarity (M) is the concentration of a solution, defined as the number of moles of solute dissolved per litre of solution. It is the most commonly used unit of concentration in chemistry.
Step-by-Step Guide
- 1Count moles of solute (mass / molar mass)
- 2Measure volume of solution in litres
- 3Molarity M = moles / litres
- 4To prepare a solution: weigh moles × molar mass of solute, dissolve, transfer to volumetric flask, add solvent to the mark
Worked Examples
Input
5.85g NaCl (M=58.5) in 500ml water
Result
0.2 M NaCl solution
moles=0.1; 0.1/0.5=0.2M
Input
0.5 mol/L × 2L
Result
1.0 mol solute needed
n = M × V
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