posted by May (PLEASE HELP) .
How many grams of sucrose (C12H22O11)
must be dissolved in 200 g water to make a solution in which the mole fraction of sucrose is 0.2?
Answer in units of g.
mole fraction sucrose = 0.2
mole fraction water = 0.8
You want 200 g water; how many moles is that?
moles = g/molar mass H2O = 200/18.015 = about 11 moles but you need to do it more precisely than that.
(11 moles H2O/total moles) = 0.8
Solve for total moles, about 14.
If total moles is 14 and moles H2O = 11, moles sucrose must be about 3 and moles = grams/molar mass should calculate g sucrose.