Question

How to calculate the number of moles of hydrogen atoms?

Answer 1

Hint: 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.