Question

Determine the empirical formula of an oxide of iron which has 59.9% and 30.1% oxygen by mass

Answer 1

100g of compound contains
Iron = 59.9g = 59.9/55.8 = 1.0mol
Oxygen = 30.1g = 30.1/16 = 1.8
Ratio of I : O = 1 : 1.8 = 5 : 9

Emperical formula = I₅O₉