# Question #d0697

Sep 29, 2017

65 moles of hydrogen atoms, or more correctly,
$3.91 \cdot {10}^{25}$ hydrogen atoms

#### Explanation:

First we calculate the number of moles of methane,
$n = \frac{w e i g h t}{m o l a r m a s s}$

$\implies n = \frac{260}{16} = 16.25$ ( molar mass of methane = 16g/mol)

Hence 16.25 moles of methane are present, which implies that number of moles of hydrogen atoms = $\left(16.25\right) \cdot \left(4\right) = 65$
This is because there are 4 hydrogen atoms in each molecule of methane.

65 moles of hydrigen atoms = $65 \cdot {N}_{A} = 65 \cdot 6.022 \cdot {10}^{23}$

which can be equivalently written as $3.91 \cdot {10}^{25}$ hydrogen atoms