# Question #33d48

##### 1 Answer
Apr 10, 2017

$3.01 \cdot {10}^{23}$

#### Explanation:

I assume you're referring to hydrogen gas.

${M}_{r}$ ${H}_{2} = 2$

First, find number of moles of hydrogen gas.

Number of moles of ${H}_{2}$ = $\frac{1 g}{2 \frac{g}{m o l}} = 0.5 m o l$

1 mol of ${H}_{2}$ has $6.02 \cdot {10}^{23}$ (Avogadro's constant) ${H}_{2}$ molecules.

Hence, 0.5 mol would have half of that which is $3.01 \cdot {10}^{23}$ molecules of ${H}_{2}$.