A solution contains 20% of ethylene glycol (C2H6O2, molar mass 62 g/mol) by mass in water. Taking 100 g of solution, the mole fraction of ethylene glycol is:

1. In 100 g solution: 20 g glycol and 80 g water. 2. Moles of glycol = $20 / 62 = 0.322$ mol; moles of water = $80 / 18 = 4.444$ mol. 3. $x_{glycol} = 0.322 / (0.322 + 4.444) = 0.322 / 4.766$. 4. $x_{glycol} = 0.068$. _Source: syllabus Chemistry Ch 1 "Solutions", p.3_