Concentration - Molar Converter

Mole per Liter (mol/L) - Molarity (M)

The most common unit of molar concentration in chemistry. 1 mol/L = 1 Molar (M). Represents the number of moles of solute dissolved in enough solvent to make one liter of total solution.

Most common use: Laboratory solution preparation, chemical reactions, and analytical chemistry. A 1 M solution contains exactly 1 mole of solute per liter of solution.

Millimol per Liter (mmol/L)

One thousandth of a mole per liter. 1 mmol/L = 0.001 mol/L = 0.001 M. Standard for dilute solutions and biological measurements.

Common in: Biochemistry, clinical chemistry, enzyme assays, ion concentration measurements, and physiological solutions.

Mole per Cubic Meter (mol/m³)

SI unit of molar concentration. 1 mol/m³ = 0.001 mol/L = 0.001 M. Used in thermodynamics and gas phase calculations.

Application: Ideal gas calculations, chemical engineering design, and scientific thermodynamic data.

Kilomol per Liter (kmol/L)

Very concentrated solutions. 1 kmol/L = 1,000 mol/L = 1,000 M. Used for extremely concentrated industrial solutions and molten salts.

Application: Concentrated acids and bases, industrial chemical processes, and specialized high-concentration solutions.

Mole per Cubic Centimeter (mol/cm³)

Fine-scale concentration unit. 1 mol/cm³ = 1,000 mol/L = 1,000 M. Used in materials science and solid-state chemistry.

Application: Solid-state chemistry, crystal structure calculations, and material density calculations.

Molar Concentration Fundamentals

Molarity is defined as:

Molarity (M) = moles of solute ÷ liters of solution

Critical distinction: The solution volume (not solvent volume) is used in the denominator. You dissolve the solute in some solvent, then dilute to the final volume mark on a volumetric flask.

Example: To make a 1 M solution of NaCl (MW=58.5 g/mol), you would:

1. Weigh 58.5 grams of NaCl
2. Dissolve in ~500 mL of water
3. Pour into a 1-liter volumetric flask
4. Add water to the 1-liter mark

Typical Molar Concentrations by Application

• Biological fluids: 0.001-0.5 M (varying by ion/molecule)
• Standard solutions: 0.01-1 M for titrations
• Buffer solutions: 0.01-1 M typically
• Enzyme assays: 0.001-0.1 M substrate
• Stock solutions: 1-10 M for dilution
• Concentrated HCl: ~12 M
• Concentrated H₂SO₄: ~18 M
• Concentrated NH₃: ~14-15 M
• Typical seawater ions: 0.5-0.6 M (NaCl)
• Physiological saline: 0.15 M (NaCl)
• Laboratory reagents: 0.001-1 M
• Trace analysis: 10⁻⁶ to 10⁻³ M

Dilution Calculations: M₁V₁ = M₂V₂

One of the most important equations in chemistry:

M₁V₁ = M₂V₂

Where M = molarity and V = volume. This allows you to calculate how much concentrated stock solution is needed to prepare a dilute solution of desired concentration.

Example: To prepare 100 mL of 0.1 M NaCl from 1 M stock solution:

1 M × V₁ = 0.1 M × 100 mL → V₁ = 10 mL

So you would take 10 mL of 1 M stock and dilute to 100 mL total.

Key Conversion Factors & Relationships

• 1 mol/L = 1,000 mmol/L = 1,000 mol/m³ = 1 Molar (M)
• 1 mmol/L = 0.001 mol/L = 1 mol/m³ = 0.001 M
• 1 kmol/L = 1,000 mol/L = 1,000,000 mmol/L = 1,000 M
• 1 mol/cm³ = 1,000,000 mol/m³ = 1,000 M
• Molarity × Molecular Weight = g/L (density-independent)
• For dilution: M₁V₁ = M₂V₂ (constant moles)
• From molarity to pH: pH = -log₁₀[H⁺] for acids
• Avogadro's number: 1 mol = 6.022 × 10²³ particles