Determine the number of molecules present in a 4.56 mol sample of methane gas (ch4); then determine the number of hydrogen atoms in the sample

Avogadro’s number is 6.02 x 10^ 23 atoms (or molecules) per mole. Through units cancellation:

Number of atoms = (4.56 mol)( 6.02 x 10^23 molecules/ mol) = 2.74 x 10^ 24 molecules

Since the C:H ratio is 1:4, 1 molecule of CH4 will have 4 atoms of hydrogen,

Therefore  number of H = 4 (2.74 x 10^24 molecules) = 1.098 x 10^ 25 atoms 

it is the most commonly accepted one