Percent composition, empirical formulas, and molecular formulas

The percent composition of a compound is the percentage of its mass contributed by each element: divide the element's total mass in one mole of the compound by the compound's molar mass and multiply by 100. Water, H2O, is about 11 percent hydrogen and 89 percent oxygen by mass (2.02 g of hydrogen out of 18.02 g). An empirical formula gives the simplest whole-number ratio of atoms in a compound, while the molecular formula gives the actual number of each atom in one molecule. Glucose's molecular formula is C6H12O6, but its empirical formula is CH2O. Chemists can work out an empirical formula from percent composition data by converting each element's mass to moles and finding the simplest whole-number ratio.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report