Question

25g glucose (C6H12O6) is mixed with 90g water and dissolved. Calculate the vapor pressure of the solution. The vapor pressure for water is 17.54 torr.

(On the answer sheet my teacher has 17.1torr but doesnt have how he got that)

Answer 1

moles of glucose = 25 g/180.16 g/mol = 0.14 mols

moles of water = 90 g/18 g/mol = 5 mols

mole fraction of water = 5/5.14 = 0.973

So,

vapor presure of solution = mole fraction of water x vapor pressure of water

                                         = 0.973 x 17.54

                                         = 17.1 torr