What mass of ethylene glycol, when mixed with 225 g H>0. will reduce the equilib

Question

What mass of ethylene glycol, when mixed with 225 g H>0. will reduce the equilibrium vapor pressure of H_2O from 1 .00 atm to 0.800 aim at 100 degree C? The molar masses of water and ethylene glycol arc 18.02 g/mol and 62.07 g/mol. respectively. Assume ideal behavior for the solution. Assuming ideal behavior, which of the following aqueous solutions should have the highest boiling point? The freezing point depression constant of water is - 1.86 C/m. If 7.50 g NaCI is dissolved in 45.0 g H_2O. the freezing point is changed by -9.71 degree C. Calculate the vant Hoff factor for NaCI. The osmotic pressure of blood is 7.65 atm at 37 degree C. What mass of glucose (C_6H_12O_6. molar mass = 180.2 g/mol) is needed to prepare 2.25 L of solution for intravenous injection? The osmotic pressure of the glucose solution must equal the osmotic pressure of blood. (R = 0.08206 L atm/mol K)

Explanation / Answer

pressure reduce from 1atm to 0.8atm
0.8 =1X
x= mole fraction of water = 0.8
no of moles of water = w/G.M.Wt
                     = 225/18 = 1.25
mole fraction of water = no of moles of water/ total no of moles
                0.8    = 1.25/1.25+x
                1+ 0.8X =1.25
                   0.8X = 0.25
                      X = 0.25/0.8 = 0.31
                      X = 0.31 moles of ethylene glycol
mass ethylene glycol    = 0.31*62 = 19.2gm >>>> answer
13. no of paticals are increses boiling point is increases.
DeltaT    = i*m*Kb
0.75m K2SO4 2K+ and so42- total three paticals i=3
0.5m Ca(NO3)2 Ca+2 and 2NO3- total three paticlas i=3

delta T = 3*0.75*kb
so 0.75m K2SO4 has highest boiling point answer ---B
14.Delta T = i*m*Kf
molality = 7.5*1000/58.5*45
         = 2.84m
-9.71   = i*2.84*-1.86
       i = 1.83 >>> answer D

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