Moles to Grams Converter (Chemistry)
Convert between moles, grams, and number of particles for any element or compound.
Enter the molar mass to perform stoichiometry conversions instantly.
The Mole Concept
The mole is the chemist’s counting unit for atoms, molecules, and ions. Just as a “dozen” always means 12 of something, a mole always means exactly 6.02214076 × 10²³ particles. This number — Avogadro’s number — was named after Italian scientist Amedeo Avogadro (1776–1856), whose work on gas volumes laid the groundwork for understanding atomic quantities.
Why 6.022 × 10²³? This number was chosen so that the molar mass of any element (in grams per mole) numerically equals its atomic mass (in atomic mass units, u). The atomic mass of carbon-12 is exactly 12 u, so one mole of carbon-12 weighs exactly 12 grams. This elegant relationship makes laboratory calculations practical.
The Core Formulas
Moles from grams: moles = mass (g) / molar mass (g/mol)
Grams from moles: mass (g) = moles × molar mass (g/mol)
Particles from moles: particles = moles × 6.022 × 10²³
Moles from particles: moles = particles / 6.022 × 10²³
Common Molar Masses
| Substance | Formula | Molar Mass (g/mol) |
|---|---|---|
| Water | H₂O | 18.015 |
| Carbon dioxide | CO₂ | 44.009 |
| Table salt | NaCl | 58.44 |
| Glucose | C₆H₁₂O₆ | 180.16 |
| Oxygen gas | O₂ | 32.00 |
| Hydrogen gas | H₂ | 2.016 |
| Sulfuric acid | H₂SO₄ | 98.07 |
| Ammonia | NH₃ | 17.03 |
| Ethanol | C₂H₅OH | 46.07 |
To find the molar mass of any compound, add the atomic masses of all atoms from the periodic table.
Worked Example
How many moles are in 36 grams of water? Molar mass of H₂O = 2(1.008) + 15.999 = 18.015 g/mol Moles = 36 / 18.015 = 1.999 mol ≈ 2.00 moles of water
How many molecules is that? Molecules = 2.00 × 6.022 × 10²³ = 1.20 × 10²⁴ water molecules
Laboratory Applications
Chemists use mole calculations constantly: weighing out precise amounts of reagents for reactions, preparing solutions of known molarity (mol/L), and calculating theoretical yields in synthesis. Without the mole concept, it would be impossible to work with atoms in a practical laboratory setting — you cannot count individual atoms, but you can weigh them precisely.