Calculate the molecular formula of an organic compound if its composition contains a mass fraction of carbon of 80%.

Calculate the molecular formula of an organic compound if its composition contains a mass fraction of carbon of 80%. The mass fraction of hydrogen is 20%, and its relative density for oxygen is 0.94. Determine which series it belongs to.

Given:
w (C) = 80%
w (H) = 20%
D (O2) = 0.94
To find:
CxHy-?
M (CxHy) -?
Decision
M (CxHy) = 0.94 * 32 grams / mol = 30 grams / mol
n (C) = 0.8 * 30/12 = 2;
n (H) = 0.2 * 30/1 = 6;
C2H6 – Ethane, belongs to the series of alkanes