% by mass concentration 1. The problem statement, all variables and given/known data An aqueous CaCL2 solution has a vapor pressure of 80.8mmHG at 50 degree C . The vapor pressure of pure water at this temperature is 92.6 mmHG . What is the concentration of CaCl2 in mass percent? 2. Relevant equations % by mass = mass solute/mass solution. 3. The attempt at a solution I tried converting the pressure into moles then dividing the moles of CaCl2 by the total moles. Im pretty stuck.. Thanks Skadoo!