Question

Determine the empirical formula for each compound from the molecular formula.

molecular formula=C3H6 empirical formula=

molecular formula=C6H12O6 empirical formula=

Answer 1

Molecular formula = C₃H₆ : empirical formula = CH₂

Molecular formula = C₆H₁₂O₆ : empirical formula = CH₂O

Explanation

Empirical formula gives the proportions of the elements present in a compound but not the actual numbers whereas molecular formula gives the actual number of different atoms present in a molecule.

(a.) Let molecular formula be C₃H₆

In one molecule of C₃H₆, there are 3 atoms of carbon and 6 atoms of hydrogen

atoms of hydrogen / atoms of carbon = (6) / (3)

atoms of hydrogen / atoms of carbon = 2

This means there are two hydrogen atoms per atom of carbon.

Empirical formula becomes CH₂

(a.) Let molecular formula be C₆H₁₂O₆

In one molecule of C₆H₁₂O₆, there are 6 atoms of carbon, 12 atoms of hydrogen and 6 atoms of oxygen

atoms of hydrogen / atoms of carbon = (12) / (6)

atoms of hydrogen / atoms of carbon = 2

atoms of oxygen / atoms of carbon = (6) / (6)

atoms of oxygen / atoms of carbon = 1

This means there are two hydrogen atoms and one oxygen atom per atom of carbon.

Empirical formula becomes CH₂O