What mass of hydrogen is in a 102.0 g quantity of methane (CH4) ?

A. 1.01 g H

B. 2.57 g H

C. 4.0 g H

D. 25.7 g H

Methane formula is CH₄. Molar mass of methane is calculated as taking the sum of molar masses of the elements multiplied by the number of atoms of the element making up the compound.

Molar mass - (molar mass of C) + (molar mass of H x 4)

= 12.01 + (1.007x4) = 16.04 g/mol

round it off to 16 g/mol

In 16 g of methane, 4.03 g of H is present

In 1 g of methane, 4.03/16 g of H

Therefore in 102 g of methane - 4.028/16 x 102 g = 25.7 g of H is present

Correct answer is D.