Empirical and molecular formulaeAQA A-Level Chemistry: Mind map

Exam questions on Empirical and molecular formulae

1. Chemists in a food laboratory identify sugars and acids from their formulae. They record that glucose has the molecular formula C₆H₁₂O₆.
   State the empirical formula of glucose and explain how it differs from its molecular formula.2 marks
2. An organic compound X contains only carbon and hydrogen. Analysis shows it contains 85.7% carbon and 14.3% hydrogen by mass, and its relative molecular mass is 56.0. Use Ar values: C = 12.0, H = 1.0.
   Calculate the molecular formula of compound X.2 marks
3. A 2.00 g sample of an iron oxide is heated in a stream of hydrogen until it is completely reduced to iron. The mass of iron produced is 1.40 g. Use Ar values: Fe = 55.8, O = 16.0.
   Calculate the amount, in mol, of iron and the amount, in mol, of oxygen in the sample.3 marks