Molarity Calculator
Calculate solution concentration
The Complete Guide to Molarity Calculations
What is Molarity?
Molarity (M) is a measure of solution concentration, defined as the number of moles of solute per liter of solution. It's a fundamental concept in chemistry used for:
- Preparing chemical solutions
- Conducting titrations
- Analyzing reaction stoichiometry
- Quantifying chemical concentrations
Molarity (M) = Moles of Solute ÷ Volume of Solution (L)
Key Equations for Molarity Calculations
Basic Molarity Formula
M = n ÷ V
Where:
- M = Molarity (mol/L)
- n = Moles of solute
- V = Volume of solution (L)
Mass Calculation
Mass = M × V × Molar Mass
Where:
- Mass = Required mass of solute (g)
- Molar Mass = Molecular weight (g/mol)
How to Calculate Molarity: Step-by-Step
Step 1: Gather Required Data
- Molarity (M) of the desired solution
- Volume (V) of the solution
- Molar mass of the solute
Step 2: Calculate Moles of Solute
Moles = Molarity × Volume
Example: For 12 M solution in 32 L:
- Moles = 12 × 32 = 384 mol
Step 3: Calculate Required Mass
Mass = Moles × Molar Mass
Example: With molar mass = 2.96 g/mol:
- Mass = 384 × 2.96 = 1136.64 g
Practical Tips for Solution Preparation
Measurement Accuracy
- Use analytical balances for precise mass measurements
- Calibrate volumetric glassware regularly
- Record measurements to appropriate significant figures
Solution Preparation
- Always add solute to solvent, not vice versa
- Use distilled or deionized water for aqueous solutions
- Label all solutions with concentration and preparation date
Molarity FAQs
How do I convert between molarity and molality?
Use the formula:Molality = Molarity ÷ (Density - (Molarity × Molar Mass))Density must be in kg/L for accurate conversion.
What's the difference between molarity and normality?
Molarity measures moles per liter, while normality accounts for reactive capacity:
- Normality = Molarity × n (n = equivalents per mole)