A 3.24-g sample of titanium reacts with oxygen to form 5.40 g of the metal oxide. What is the empirical formula of the metal oxide? GIVEN: 3.24 g Ti 5.40 g metal oxide FIND: empirical formula You cannot convert mass of metal oxide into moles because you would need its formula, and that is what you are trying to find. You are given the mass of the initial Ti sample and the mass of its oxide after the sample reacts with oxygen.
The difference is the mass of oxygen that combined with the titanium.