To use combustion analysis data to determine an empirical formula.
A molecular formula expresses the number of each kind of atom in a molecule. For example, the molecular formula for propene, C3H6, indicates three carbon atoms and six hydrogen atoms per molecule. This also means that one mole of propene contains three moles of carbon and six moles of hydrogen.
An empirical formula expresses the mole ratio of the elements. The empirical formula for propene is CH2, indicating twice as much hydrogen as carbon. When analyzing unknown compounds in a lab, it is often possible to identify the mole ratios, and thus the empirical formula, but not the molecular formula.
Notice that the molecular mass of propene, 3(12) + 6(1) = 42 amu, is a multiple of the empirical formula mass, 1(12) + 2(1) = 14 amu.
If 4.50 g of the unknown compound contained 0.150 mol of C and 0.300 mol of H, how many moles of oxygen, O, were in the sample?
Express your answer to three significant figures and include the appropriate units.