Question

_______ grams of methane contains as many hydrogen atoms as there are in 4 grams of hydrogen gas.

Answer 1

Molecular weight of hydrogen is 2 and in one hydrogen molecule 2 atoms of hydrogen are present. Hence, no. of atoms present in $4g$ of $H_2=4/2\times 2Na=4Na$ (1)

One molecule of methane contains 4 atoms of Hydrogen. Let amount of methane be ${}^{\prime }{x}^{\prime }g$. Hence, no. of atoms present in ${}^{\prime }{x}^{\prime }g$ of $C{H}_4=x/16\times 4.Na=x/4.Na$ (2)

Hence, $x/4.Na=4Na$ (from 1 and 2)

$x=16g$