Avogadro's number is the number of \( \begin{array}{l}\text { particles in } 1 \text { mole of a substance. } \\ \text { grams in } 1 \text { mole of a substance. } \\ \text { moles in } 6.02 \times 10^{23} \mathrm{amu} \text { of an element. } \\ \text { moles in } 6.02 \times 10^{23} \text { grams of an element. } \\ \text { amu in } 1 \text { mole of a substance. }\end{array} \)

Avogadro's number, approximately \(6.02 \times 10^{23}\), is a cornerstone of chemistry that represents the number of atoms, molecules, or particles in one mole of a substance. This incredibly large number is essential for converting between the macroscopic scale of substances we work with daily and the microscopic scale of atoms and molecules, allowing chemists to quantify and manipulate matter effectively. In practical terms, Avogadro's number allows us to conduct real-world applications, like determining the number of molecules in a given volume of a gas at standard temperature and pressure. For example, knowing that one mole of any gas at STP occupies approximately 22.4 liters means you can easily calculate how many molecules fit into your favorite fizzy drink or how many moles of a substance you have by measuring its volume—science made fun and approachable!