15g ethanol is dissolved in enough water to make 150ml solution. The solution de
ID: 960614 • Letter: 1
Question
15g ethanol is dissolved in enough water to make 150ml solution. The solution density is 0.981g/ml. (A) calculate the molality of ethanol in solution (B) calculate the mole fraction of ethanol and water in solution. 15g ethanol is dissolved in enough water to make 150ml solution. The solution density is 0.981g/ml. (A) calculate the molality of ethanol in solution (B) calculate the mole fraction of ethanol and water in solution. 15g ethanol is dissolved in enough water to make 150ml solution. The solution density is 0.981g/ml. (A) calculate the molality of ethanol in solution (B) calculate the mole fraction of ethanol and water in solution.Explanation / Answer
A)
density = 0.981 g/ml
mass of ethanol = 15 g
moles = 15 / 46 = 0.326
volume = 150 mL = 0.15 L
Molarity = moles / volume = 0.326 / 0.150 = 2.17
Molarity = 2.17 M
B)
moles of ethanol = 0.326
mass of solution = 150 x 0.981 = 147.15 g
mass of solvent = 147.15 - 15 = 132.15 g
moles of water = 132.15 / 18 = 7.34
total moles = 7.34 + 0.326 = 7.666
mole fraction of ethanol = 0.326 / 7.666 = 0.0425
mole fraction of water = 7.34 / 7.666 = 0.958