What is the density of methane in terms of hydrogen?

Given:
Methane – CH4

To find:
D H2 (CH4) -?

Decision:
1) Using the periodic system of D.I.Mendeleev, calculate the molar masses of CH4 and H2:
M (CH4) = Mr (CH4) = Ar (C) * N (C) + Ar (H) * N (H) = 12 * 1 + 1 * 4 = 16 g / mol;
M (H2) = Mr (H2) = Ar (H) * N (H) = 1 * 2 = 2 g / mol;
2) Calculate the relative density of CH4 by H2:
D H2 (CH4) = M (CH4) / M (H2) = 16/2 = 8.

Answer: The relative density of methane to hydrogen is 8.