18. Determine the empirical formula of a substance that consists of 72.02g manganese and 27.98g oxygen. A) MnO2 B) Mn3O4 C) Mn2O3 D) MnO 19. A compound with an empirical formula of CH2O and a molar mass of 180.18g/mol. What is the molecular formula of this compound? A) C6H12O6 B) C3H6O10 C) C3H10O2 D) Cs3H2O3 20. Dixanthogen, an herbicide, is composed of 29.73% carbon, 4.16% hydrogen, 13.20% oxygen, and 52.91% sulfur. It has a molar mass of 242.4g/mol. Determine the empirical and the molecular formulas