Calculations · Learning guide

Moles connect particles to mass

The mole lets chemists describe enormous numbers of particles using practical amounts of material.

Count by amount

One mole contains exactly 6.02214076 × 10²³ specified elementary entities. Specify what you mean: atoms, molecules, ions or another defined group.

Use the units

Amount in moles equals mass in grams divided by molar mass in grams per mole. For 36.03 g of water at 18.015 g/mol, the amount is 2 mol. The units cancel cleanly.

Avoid a common mistake

Molar mass and sample mass are different. Doubling a sample doubles its mass and amount, but does not change the substance’s molar mass.

Learning boundary

This portal teaches calculations. Do not use it to select chemical doses, mix household products or plan unsupervised experiments.

Further reading: Reference source ↗. Written for this starter collection. Check primary references for specialised use.