Example 2 - Empirical Formula

From an experiment, a scientist found that a hydrocarbon contains 85.7% of carbon according to its mass. Find the empirical formula of the hydrocarbon. [Relative atomic mass: Carbon = 12; Hydrogen = 1]

Answer:

Element
C
H
Percentage
85.7%
14.3%
Mass in 100g
85.7g
14.3g
Number of mole
85.7 12 =7.142mol
14.3 1 =14.3mol
Simple ratio
7.142 7.142 =1
14.3 7.142 =2


The empirical formula of the hydrocarbon = CH2