Practice question
Question
What is the mole fraction of methanol (molar mass = 32 g/mol) in a solution containing 16 g of methanol and 72 g of water?
Explanation
Moles of methanol = (16/32) = 0.5 mol . Moles of water = (72/18) = 4 mol . Total moles = 0.5 + 4 = 4.5 . Mole fraction = (0.5/4.5) ≈ 0.111 .