Molarity Calculator

Calculate molar concentration, solution strength, and concentration in different units. Molarity is the number of moles of solute per liter of solution.

Molarity Calculator Results

Enter the mass, molecular weight, and volume to calculate molarity and concentration.

What is Molarity?

Molarity (M) is a measure of the concentration of a solute in a solution, defined as the number of moles of solute per liter of solution. It's one of the most commonly used concentration units in chemistry.

The formula for molarity is:

M = n / V

Where:

  • M = Molarity (mol/L)
  • n = Number of moles of solute
  • V = Volume of solution in liters

How to Calculate Molarity

To calculate molarity, you need to know the mass of the solute, its molecular weight, and the volume of the solution:

  1. Convert mass to moles: Divide the mass of solute by its molecular weight
  2. Convert volume to liters: Ensure the volume is in liters
  3. Calculate molarity: Divide moles by volume in liters

Example: If you have 3g of NaCl (molecular weight = 58.44 g/mol) dissolved in 5L of water, the molarity would be:

Moles = 3g ÷ 58.44 g/mol = 0.0513 mol

Molarity = 0.0513 mol ÷ 5L = 0.0103 M

Molarity vs Other Concentration Units

Unit Definition Formula
Molarity (M) Moles per liter of solution mol/L
Molality (m) Moles per kilogram of solvent mol/kg
Mass % Mass of solute per 100g solution g/100g
ppm Parts per million mg/L

Applications of Molarity

Laboratory Work

Preparing standard solutions, titrations, and analytical chemistry applications.

Industrial Processes

Chemical manufacturing, quality control, and process optimization.

Pharmaceuticals

Drug formulation, dosage calculations, and therapeutic solutions.

Environmental Science

Water treatment, pollution monitoring, and environmental analysis.

Frequently Asked Questions

What's the difference between molarity and molality?

Molarity is moles per liter of solution, while molality is moles per kilogram of solvent. Molarity changes with temperature due to volume changes, but molality remains constant.

Why is molarity temperature-dependent?

Molarity depends on volume, which changes with temperature. For precise work, molality is often preferred as it's temperature-independent.

How do I convert between different concentration units?

Use the density of the solution and molecular weight to convert between molarity, mass percent, and other units. Our calculator handles these conversions automatically.

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