how to find percent composition of oxygen in KCLO3
3 The theoretical value of the % oxygen in potassium chlorate is calculated from the formula KClO 3 with a molar mass = 122.6 g/mol. Frequently it is interesting â and instructive-to determine the percent error of an experimental. determination.ou will calculate the theoretical value from the chemical formula and compare your experimental value to the theoretical value. Background: When potassium chlorate (KClO. 3) is heated, it undergoes chemical decomposition. Oxygen gas (O 2) is given off and potassium chloride (KCl) remains as the residue.