Step 1:-Given compound = nitrogen oxide Given mass of Oxygen (O)=69.6 %We assume that total mass of compound= 100 g Empirical Formula:-It defined the simplest whole number ratio of atoms of each elements presents in the molecules of the substance.For the calculation of Empirical formula first of all we have to calculate the mass of each element.Calculation of mass of nitrogen in the given compound.Given mass of Oxygen (O)=69.6 %We assume that total mass of compound= 100 g 100 g of the compound contains 69.6 % of O Therefore 69.6 % of 100g of compound contains= =69.6 g of Oxygen Now we calculate the mass of nitrogen,Mass of Nitrogen = Mass of compound- mass of oxygen =100 g - 69.6 g=30.4 g.