What does grams per mole (g/mol) mean?

Grams per mole is the unit of molar mass. It expresses how many grams of a substance make up exactly one mole (6.02214076 × 10²³ particles). For example, water has a molar mass of 18.015 g/mol, meaning 18.015 grams of water contains one mole of water molecules.

How do I convert grams to moles?

Divide the mass in grams by the molar mass: n = m / M. For example, 36 g of water (M = 18.015 g/mol) gives n = 36 / 18.015 ≈ 1.999 mol.

How do I convert moles to grams?

Multiply the number of moles by the molar mass: m = n × M. For example, 2.5 mol of NaCl (M = 58.443 g/mol) gives m = 2.5 × 58.443 = 146.11 g.

Where do I find the molar mass of a compound?

The molar mass equals the sum of the atomic weights (in g/mol) of all atoms in the molecular formula. You can look it up in a periodic table or chemistry reference, or use this calculator's preset list for common compounds.

What is the difference between molar mass and molecular weight?

They are numerically equal. Molecular weight (relative molecular mass) is dimensionless; molar mass is expressed in g/mol. In practice, both terms are used interchangeably in lab work.

Grams Per Mole Calculator

Enter a molar mass and a mass in grams or a number of moles — the other value is calculated instantly.