Percentage Concentration to Molarity Calculator
Convert between percentage concentration and molarity using density and molar mass
Convert Concentration Units
Automatically fills molar mass and typical density
Mass of one mole of the substance
Density of the final solution
Mass percentage of solute in solution
Formulas Used
Percentage to Molarity: M = (% × Density in g/L) ÷ (Molar Mass × 100)
Molarity to Percentage: % = (M × Molar Mass × 100) ÷ Density in g/L
Units: M = mol/L, Density = g/L, Molar Mass = g/mol
Example Calculation
Hydrochloric Acid Solution
Goal: Convert 37% HCl solution to molarity
Given: 37% HCl, density = 1.18 g/cm³, molar mass = 36.46 g/mol
Step-by-Step Solution
1. Convert density: 1.18 g/cm³ = 1180 g/L
2. Apply formula: M = (37% × 1180 g/L) ÷ (36.46 g/mol × 100)
3. Calculate: M = 43660 ÷ 3646 = 11.98 mol/L
Result: 37% HCl solution = 12.0 M
Common Substances
Ammonia (NH₃)
MW: 17.03 g/mol | ρ: 0.8826 g/cm³
Acetic Acid (CH₃COOH)
MW: 60.05 g/mol | ρ: 1.0492 g/cm³
Ethanol (C₂H₅OH)
MW: 46.07 g/mol | ρ: 0.7893 g/cm³
Formaldehyde (CH₂O)
MW: 30.03 g/mol | ρ: 0.815 g/cm³
Glucose (C₆H₁₂O₆)
MW: 180.16 g/mol | ρ: 1.54 g/cm³
Hydrochloric Acid (HCl)
MW: 36.46 g/mol | ρ: 1.18 g/cm³
Hydrogen Peroxide (H₂O₂)
MW: 34.01 g/mol | ρ: 1.45 g/cm³
Nitric Acid (HNO₃)
MW: 63.01 g/mol | ρ: 1.51 g/cm³
Phosphoric Acid (H₃PO₄)
MW: 97.99 g/mol | ρ: 1.885 g/cm³
Potassium Hydroxide (KOH)
MW: 56.11 g/mol | ρ: 2.044 g/cm³
Sodium Chloride (NaCl)
MW: 58.44 g/mol | ρ: 2.165 g/cm³
Sodium Hydroxide (NaOH)
MW: 40 g/mol | ρ: 2.13 g/cm³
Sulfuric Acid (H₂SO₄)
MW: 98.08 g/mol | ρ: 1.84 g/cm³
Water (H₂O)
MW: 18.015 g/mol | ρ: 1 g/cm³
Conversion Tips
Molar mass equals molecular weight numerically
Density changes with concentration and temperature
Use solution density, not pure solute density
1 M = 1 mol/L = 1 mol/dm³
Check conditions: temperature and pressure matter
Understanding Concentration Conversions
What is Molarity?
Molarity (M) is the number of moles of solute per liter of solution. It's one of the most common ways to express concentration in chemistry. 1 M = 1 mol/L = 1 mol/dm³.
What is Percentage Concentration?
Percentage concentration (mass%) is the mass of solute divided by the total mass of solution, multiplied by 100. It's commonly used for commercial solutions and reagents.
Applications
- •Laboratory solution preparation
- •Analytical chemistry calculations
- •Industrial process control
- •Quality control and standardization
Key Formulas
M = (% × ρ) ÷ (MW × 100)
% = (M × MW × 100) ÷ ρ
Variable Definitions
- M: Molarity (mol/L)
- %: Mass percentage (%)
- ρ: Solution density (g/L)
- MW: Molar mass (g/mol)
Important: Always use the density of the solution, not the pure solvent or solute.