Question

How to calculate the number of moles of hydrogen atoms?

Answer 1

In order to answer this question, to calculate the number of moles of hydrogen atoms, first we will take a compound included with hydrogen atoms and then go further to calculate the number of moles of hydrogen atoms.

Complete answer:
The molecular formula of methane $(C{H_4})$ suggests that one molecule of this compound consists of 4 atoms of $H$ .
So $1{\text{ }}mole{\text{ }}of\;C{H_4}$ will have $4{\text{ }}mol$ atom of Hydrogen.
Now number of moles of $C{H_4}$ in $5.2 \times {10^{24}}\;molecules$ is:
$= \dfrac{{5.2 \times {{10}^{24}}}}{{Avogadro's\,number}}$
So the number of moles of $H$ atom in it:
= \dfrac{{4 \times 5.2 \times {{10}^{24}}}}{{Avogadro's\,number}} \\\
$= \dfrac{{4 \times 5.2 \times {{10}^{24}}}}{{6.024 \times {{10}^{23}}}} \approx 34.5mol\,atom$
**Hence, $34.5mol\,atom$ of hydrogen is present in methane.

Note: **
Isotopes 1 $H$ is the most common hydrogen isotope, with an abundance of more than $99.98\%$. Because the nucleus of this isotope... 2 $H$ , the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in the nucleus.