What is Avogadro's Number ?

Avogadro's number is the number of particles present in one mole of any substance. Its value is 6.022 × 10²³. It is named after the Italian scientist Amedeo Avogadro.

Example 1:
1 mole of sodium (Na) contains 6.022 × 10²³ atoms of sodium.

Example 2:
1 mole of NaCl contains 6.022 × 10²³ formula units of NaCl.

Example 3:
2 moles of CO₂ contains 2 × 6.022 × 10²³ = 1.204 × 10²⁴ molecules of CO₂.