# How many molecules are in 10.0 moles of H2O?

Sep 4, 2016

Well, in one mole of stuff there are $\text{Avogadro's Number, } {N}_{A}$, individual items of stuff.

#### Explanation:

$\text{Avogadro's Number,}$ ${N}_{A}$, $= 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$.

$10.0 \cdot m o l \times {N}_{A} = 10.0 \cdot \cancel{m o l} \times 6.022 \times {10}^{23} \cdot \cancel{m o {l}^{-} 1}$

$=$ $6.022 \times {10}^{24} \text{ individual water molecules.}$

Note that had you been asked $\text{how many eggs are in 2 dozen eggs}$ I think you would have very very quickly given the answer. ${N}_{A}$ is a collective number like the $\text{dozen}$; the only difference is that ${N}_{A}$ is monumentally larger.