# How does Avogadro's number relate to atomic mass?

1 mole contains approximately $6.02 \cdot {10}^{23}$ atoms or molecules (depending on what is being talked abotu, whether number of water molecules, atoms of magnesium or total atoms in $\text{NaCl}$)
So for example, water has a mass of around $18 g$ $m o {l}^{-} 1$, this means that 18g of water contains $6.02 \cdot {10}^{23}$ water molecules, but $1.806 \cdot {10}^{24}$ atoms (three atoms per water molecule).
Anther example, magnesium has a mass of around $24.3 g$ $m o {l}^{-} 1$, and 10g contains $\frac{10}{24.3} \approx 0.412 m o l$ of Mg. $0.412 \left(6.02 \cdot {10}^{23}\right) \approx 2.48 \cdot {10}^{23}$ atoms