Molarity Calculator

Calculate solution concentration, moles, volume, and perform dilution calculations

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Molarity Formula

M = n / V

Molarity = moles of solute ÷ liters of solution

Current Formula:

Result

Step-by-Step Solution

Common Laboratory Solutions

Solution Molarity

Common Compounds

Formula Name Molar Mass

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About Molarity Calculator

What is Molarity?

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

Molarity Formula: M = n / V

Where:

  • M = Molarity (mol/L or M)
  • n = number of moles of solute (mol)
  • V = volume of solution (L)

How to Use This Calculator

  1. Select calculation mode: Choose what you want to calculate (molarity, moles, volume, from mass, or dilution)
  2. Enter your values: Input the known quantities
  3. Get instant results: See the answer with step-by-step explanation

Key Formulas

Calculate Molarity

M = n / V

Molarity equals moles divided by volume in liters.

Calculate Moles

n = M × V

Moles equals molarity times volume.

Calculate Volume

V = n / M

Volume equals moles divided by molarity.

From Mass

M = (mass / molar mass) / V

First convert mass to moles using molar mass, then divide by volume.

Dilution Formula

M₁V₁ = M₂V₂

The product of initial concentration and volume equals the product of final concentration and volume.

Examples

Example 1: Calculate Molarity

What is the molarity of a solution containing 2 moles of NaCl in 500 mL of solution?

  • Convert volume: 500 mL = 0.5 L
  • M = 2 mol / 0.5 L = 4 M

Example 2: Dilution Calculation

How much water should be added to dilute 100 mL of 6M HCl to make 2M HCl?

  • Using M₁V₁ = M₂V₂
  • 6M × 100 mL = 2M × V₂
  • V₂ = 300 mL
  • Add 200 mL of water

Common Laboratory Solutions

Solution Typical Concentration
Concentrated HCl 12 M
Concentrated H₂SO₄ 18 M
Concentrated HNO₃ 16 M
Concentrated NaOH 19 M
Saline (NaCl) 0.154 M (0.9%)
Household bleach (NaOCl) ~0.8 M

Applications

  • Laboratory Preparations: Preparing solutions of specific concentrations
  • Chemical Analysis: Titrations and quantitative analysis
  • Pharmaceutical Industry: Drug formulation and dosing
  • Educational Settings: Chemistry coursework and experiments
  • Industrial Processes: Manufacturing and quality control

Frequently Asked Questions

What is the difference between molarity and molality?

Molarity (M) is moles per liter of solution, while molality (m) is moles per kilogram of solvent. Molarity changes with temperature because volume changes, but molality doesn't.

Why is molarity important?

Molarity allows chemists to know exactly how many molecules or ions are present in a given volume, which is essential for stoichiometric calculations in chemical reactions.

Can molarity be greater than the number of moles?

Yes, when the volume is less than 1 liter. For example, 2 moles in 0.5 L gives 4 M.

Tip: Always make sure your volume is in liters before calculating molarity! A common mistake is using milliliters without converting.