The Mole and Counting Atoms

Manual: General · Subject: Chemistry

Learn the chemistry counting unit and how chemists connect particles, mass, and formulas.

Why chemists need a counting unit

Atoms and molecules are far too small to count one by one, so chemists use the mole. One mole is a counting unit, like a dozen, but much larger.

One mole contains $6.02 \times 10^{23}$ particles. This number is called Avogadro's number.

The mass of one mole of a substance in grams is called its molar mass. Molar mass connects the tiny world of atoms to measurable laboratory amounts.

One mole contains approximately how many particles?

6.02 \times 10^{23}

6.02 \times 10^{3}

3.14 \times 10^{2}

1.00 \times 10^{1}

What is a mole in chemistry?

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Quick connection

Mass tells you how much sample you have, while the mole tells you how many particles are in that sample.

Why do chemists use the mole?

To avoid measuring substances To count tiny particles in manageable units To replace the periodic table To identify colors