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Molar Mass Calculator

Calculate the molar mass (molecular weight) of any chemical compound. Enter a chemical formula to get the molar mass in g/mol with element-wise breakdown and percentage composition.

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Molar Mass of H2SO4

98.077 g/mol

ElementAtomsAtomic MassContribution%
H(Hydrogen)21.0082.0162.1%
S(Sulphur)132.06532.06532.7%
O(Oxygen)415.99963.99665.3%

Common Compounds

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How Molar Mass is Calculated

M = Σ (atomic mass × number of atoms)

Example — H₂SO₄ (Sulphuric Acid):

  • H: 2 × 1.008 = 2.016 g/mol
  • S: 1 × 32.065 = 32.065 g/mol
  • O: 4 × 15.999 = 63.996 g/mol
  • Total = 2.016 + 32.065 + 63.996 = 98.077 g/mol

Frequently Asked Questions

What is molar mass and why is it important?

Molar mass is the mass of one mole (6.022 × 10²³ particles) of a substance, measured in g/mol. It is essential for stoichiometry — converting between grams and moles in chemical calculations. For example, 1 mole of water (H₂O) weighs 18.015 g.

Multiply the atomic mass of each element by the number of atoms of that element in the formula, then add all contributions. For H₂SO₄: H = 2 × 1.008 = 2.016, S = 1 × 32.065 = 32.065, O = 4 × 15.999 = 63.996. Total = 98.077 g/mol.

Molecular mass (or molecular weight) is the mass of a single molecule measured in atomic mass units (amu). Molar mass is the mass of one mole of molecules measured in g/mol. Numerically, they are equal — just different units.

Molar mass is used in stoichiometry (CBSE Class 11 Chapter 1), calculating molarity and molality, gas law calculations, percentage composition, empirical and molecular formula determination — all frequently asked in CBSE, JEE, and NEET.