Assuming 100 grams of the compound, we can convert the masses to the number of moles using the atomic masses: 53.5 g * 1 mol C / 12.0107 g C = 4.45 mol C 15.5 g * 1 mol H / 1.00794 g H = 15.38 mol H 31.1 g * 1 mol N / 14.0067 g N = 2.22 mol N
We divide the number of moles of each element by the lowest number of moles, in this case, we divide by 2.22: C 4.45/2.22 = 2.00 H 15.38/2.22 = 6.93 ≈ 7 N 2.22/2.22 = 1
Therefore we can write the empirical formula using the number of moles calculated as the subscript for each element: C2H7N
Empirical formula is the simplest ratio of whole numbers of components making up a compound. since percentage compositions have been given, we can calculate the masses of elements in 100 g of the compound carbon hydrogen nitrogen mass 53.5 g 15.5 g 31.1 g number of moles 53.5/12 15.5/1 31.1 / 14 = 4.46 = 15.5 = 2.22 divide by least number of moles 4.46/2.22 = 2.0 15.5/2.22 = 6.9 2.22/2.22 = 1 numbers rounded off C - 2 H - 7 N - 1 Then empirical formula - C₂H₇N
