Molar Mass and the Mole Concept
The mole is the fundamental unit for counting atoms and molecules in chemistry. One mole contains 6.022 × 10²³ particles (Avogadro's number). Molar mass (g/mol) is the mass of one mole of a substance, numerically equal to its molecular weight. This calculator solves for moles, mass, or molar mass using n = m/M. Mass can be entered in g, mg, or kg.
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Formula
Molar Mass Calculator
Calculate moles or mass of a substance using n = m/M.
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Worked Example
Given:
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FAQs
How do I find the molar mass of a compound?
Add the atomic masses of all atoms in the molecular formula. For H₂O: 2(1.008) + 16.00 = 18.016 g/mol. For NaCl: 22.99 + 35.45 = 58.44 g/mol. Atomic masses are found on the periodic table.
Why is the mole such an important concept in chemistry?
Chemical reactions occur between atoms in fixed ratios. The mole allows chemists to work with countable quantities of atoms using measurable masses. Without it, calculating stoichiometry would require working with individual atoms — far too small to weigh.
What is Avogadro's number?
Avogadro's number (6.022 × 10²³) is the number of atoms, molecules, or particles in one mole. It was defined so that 12 g of carbon-12 contains exactly one mole of atoms.