Science · grade HS (10) · lesson
Chemistry: the mole and stoichiometry (grade 10)
Atoms are too small to count one by one, so chemists count them in moles. Moles let you turn a balanced equation into grams you can weigh.
The mole is a count
💡 One mole is about 6.02 × 10²³ particles, the same number for any substance.
A mole is a counting unit, like a dozen, only far bigger: about 6.02 × 10²³ particles.
A mole of any substance has the same number of particles. But a mole of heavier atoms has more mass, just as a dozen bowling balls outweighs a dozen marbles.
🧠 How to think about it
2.0 mol × 6.0 × 10²³ = 12 × 10²³. Scientific notation keeps one digit before the decimal, so write it as 1.2 × 10²⁴.
- mole
- about 6.02 × 10²³ particles
- Avogadro's number
- 6.02 × 10²³