glycol is used as an automobile antifreeze and in the manufacture of polyester fibers. The name of glycol stems from the sweet taste of this poisonous compound. Combustion of 6.38g of ethylene glycol gives 9.06mg CO2 and 5.5mg of H2O. The compound contains only C, H, and O. What are the percentage of the elements in ethylene glycol?

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%