Question

what is the molarity? calculate the molarity of solution containing 0.652 mol of glucose C6h12o6 in 255000 g of water

a solution contains 150.0 g of water (mw = 18.0 g/mol) and 50 g of ethanol (MW = 44.0 g/mol ) wat are the mole fraction of water and ethanol,and vapor pressure of the solution at 25 C (p water = 23.8 torr; p ethanol =58.7 torr)

Answer 1

molarity = (w/mwt)*(1000/V)

         = n*(1000/V in ml)

lets assume volume of water = volume of solution = 255000 ml

          = 0.652*(1000/255000)

molarity = 2.55*10^-3 M

Molefraction of solute = no of mole of solute/no of mole of total components.

Molefraction of water = (150/18)/((150/18)+(50/44)) = 0.88

Molefraction of ethanol = (50/44)/((150/18)+(50/44)) = 0.12

Vapor pressure of water in solution = Xwater*P0

                                     = 0.88*23.8

                                     = 20.94 torr

Vapor pressure of ethanol in solution = Xethanol*P0

                                        = 0.12*58.7

                                        = 7.044 torr

   total vapor pressure of solution = 20.94+7.044 = 27.984 torr