M

Molarity

M = n (mol) / V (L)
Quick Reference
Formula / NotationM = n (mol) / V (L)
Also Known AsMolar concentration, Concentration (C)

What is Molarity?

A concentration unit defined as the number of moles of solute per liter of solution (mol/L), symbol M. Molarity is the most common concentration unit in chemistry. It changes with temperature because volume changes with temperature. Used in stoichiometry calculations.

Formula & Notation

M = n (mol) / V (L)

Other Names / Synonyms: Molar concentration, Concentration (C)

Properties & Characteristics

SI unit: mol/L (also mol/dm³, abbreviated M). Dilution law: C1V1 = C2V2. Laboratory concentrations: concentrated HCl ≈ 12 M, concentrated H₂SO₄ ≈ 18 M, NaOH stock solutions ≈ 10 M, seawater NaCl ≈ 0.6 M. Differs from molality (mol/kg solvent) — molarity changes with temperature because volume changes. At very low concentrations (dilute aqueous), molarity ≈ molality.

Uses & Applications

Preparing analytical solutions for titrations, reactions, and biological assays. Calculating volumes needed for reactions. Serial dilutions in microbiology and biochemistry. Drug concentration in pharmacology (serum glucose ≈ 5 mM). Buffer preparation. Instrument calibration. Industrial process control.

Safety Information

Always add concentrated acid to water (never water to acid) when preparing solutions — mixing order prevents violent heat generation. Use volumetric glassware for accurate concentrations. Wear PPE including gloves and goggles when handling concentrated solutions.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Molarity
Formula M = n (mol) / V (L)
Synonyms Molar concentration, Concentration (C)

Frequently Asked Questions

A concentration unit defined as the number of moles of solute per liter of solution (mol/L), symbol M. Molarity is the most common concentration unit in chemistry. It changes with temperature because volume changes with temperature. Used in stoichiometry calculations.

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