# How many water molecules in a 4.5*mol quantity of water?

$4.5 \times {N}_{A}$, where............
$4.5 \times {N}_{A}$, where ${N}_{A} = \text{Avogadro's Number} = 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$.
$\text{The mole}$ is simply a number, like a dozen, or a score, or a gross. The mole has a special property. $1 \cdot m o l$ of ""^1H atoms has a mass of $1 \cdot g$.