# How many molecules of dioxygen are associated with a 3.2*g mass of this gas?

Jun 8, 2017

We use the molar quantity..........and get approx. $1 \times {10}^{24}$ molecules of ${O}_{2}$.

#### Explanation:

We know that $\text{Avogadro's Number}$, ${N}_{A} \equiv 6.022 \times {10}^{23} \cdot m o l$.

And so to find the number of oxygen MOLECULES, we divide the mass by the molar mass, and multiply by $\text{Avogadro's Number}$.

$\text{Number of oxygen molecules..........}$

$= \left(\frac{0.0032 \cdot k g}{0.018 \cdot k g \cdot m o {l}^{-} 1}\right) \times 6.022 \times {10}^{23} \cdot \text{molecules"*mol^-1=??"molecules}$