Molar Mass Calculator

Quick answer

Molar Mass Calculator

Calculate the molar mass of chemical compounds with detailed element breakdown and percent composition analysis.

Chemical Formula

Use standard chemical notation: H2O, CO2, CaCO3, etc.

Common Compounds

Quick Reference

Formula Guidelines

  • • Use standard element symbols (H, O, C, etc.)
  • • Numbers go after the element (H2, O2)
  • • Use parentheses for groups: Ca(OH)2
  • • Case sensitive: Co (cobalt) vs CO (carbon monoxide)
  • • No spaces in formula

Common Elements

H1.008
C12.01
N14.01
O16.00
Na22.99
Cl35.45
Ca40.08
Fe55.85

Applications

  • • Stoichiometry calculations
  • • Solution concentration
  • • Chemical reaction balancing
  • • Laboratory preparations
  • • Analytical chemistry

💡 Tips

  • • Double-check element symbols
  • • Count atoms carefully in complex formulas
  • • Use parentheses for polyatomic ions
  • • Remember subscripts multiply everything in parentheses

ℹ️ What is Molar Mass Calculator?

A molar mass calculator determines the molecular weight of a chemical compound by summing the atomic masses of all atoms in its formula. Molar mass (in g/mol) is fundamental to stoichiometry, allowing conversion between grams and moles — the bridge between lab measurements and chemical equations.

📐 Formula

Molar Mass = Σ(Number of atoms × Atomic mass of element)
Atomic Mass— Mass of one atom in atomic mass units (u) — from periodic table
Molar Mass— Mass of one mole (6.022×10²³ molecules) in g/mol
n = m/M— Moles = mass in grams / molar mass

✏️ Worked Example

Compound: H₂SO₄ (Sulfuric acid)
  1. 1H: 2 atoms × 1.008 g/mol = 2.016
  2. 2S: 1 atom × 32.06 g/mol = 32.06
  3. 3O: 4 atoms × 16.00 g/mol = 64.00
  4. 4Molar mass = 2.016 + 32.06 + 64.00 = 98.08 g/mol
  5. 5In 196g of H₂SO₄: n = 196 / 98.08 = 2.0 moles
✅ Result: Molar mass of H₂SO₄ = 98.08 g/mol

💡 How to Interpret Results

  • ▸Molar mass numerically equals the formula mass in atomic mass units (g/mol = amu/molecule).
  • ▸To find moles: n = mass(g) / molar mass(g/mol)
  • ▸To find mass: m = n × molar mass
  • ▸Molarity (M) = moles of solute / liters of solution — requires molar mass for preparation.
  • ▸Percent composition = (element mass contribution / molar mass) × 100

❓ Frequently Asked Questions

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