What mass of ethylene glycol when mixed with 225 g H2O will
What mass of ethylene glycol, when mixed with 225 g H2O, will reduce the equilibrium vapor pressure of
H2O from 1.00 atm to 0.800 atm at 100
Solution
(P-Po)/Po = X(b) * Po , Po = 1, P = 0.8 ,
Xb = mol fraction of solute ,
(1-0.8)/1 = 1(Xb) ,
Xb = 0.2,
Xb = moles of glycol/(moles of glycol + moles of water),
moles of water = 225/18 = 12.5, hence
Xb = 0.2 = (m/m+12.5) ,
m= moles of glycol = 3.125 ,
moles = 3.125 = mass/(62.07) ,
mass of glycol = 193.96 gm
