If molar mass of compound is 180.18 g/mol and of that mass 39.99 % is Carbon ∴ molar mass of carbon in compound = 180.18 g/mol × (39.99 ÷ 100) = 72 g/mol since a single carbon = 12 g/mol then number of carbons in compound = 72 ÷ 12 g/mol = 6 CARBON atoms -------------------------------------------------------------------------------------------------- If molar mass of compound is 180.18 g/mol and of that mass 6.73 % is hydrogen ∴ molar mass of hydrogen in compound = 180.18 g/mol × (6.73 ÷ 100) ≈ 12 g/mol since a single hydrogen = 1 g/mol then number of hydrogen in compound = 12 ÷ 1 g/mol = 12 HYDROGEN atoms ----------------------------------------------------------------------------------------------------- If molar mass of compound is 180.18 g/mol and of that mass 53.28 % is Oxygen ∴ molar mass of oxygen in compound = 180.18 g/mol × (53.28 ÷ 100) ≈ 96 g/mol since a single oxygen= 16 g/mol then number of oxygen in compound = 96 ÷ 16 g/mol = 6 OXYGEN atoms
∴ molecular formula of compound (aldehexose sugar e.g. glucose) = C₆H₁₂O₆
