empirical formula is the simplest ratio of whole numbers of components in a compound molecular formula is the actual ratio of components in a compound . the molecular formula for the compounds given are as follows ethyne - C₂H₂ ethene - C₂H₄ ethane - C₂H₆ methane - CH₄ the actual ratios of the elements simplified ratio C : H C : H ethyne 2:2 1:1 ethene 2:4 1:2 ethane 2:6 1:3 methane 1:4 1:4 the only compound where the actual ratio is equal to the simplified ratio is methane therefore in methane molecular formula CH₄ is the same as empirical formula CH₄