Calculate the vapor pressure of a solution of 0.99 mol of cholesterol in 5.4 mol of toluene at 32°c. pure toluene has a vapor pressure of 41 torr at 32°c. (assume ideal behavior.)

Explanation:

No. of moles of cholesterol solute, = 0.99 mol

No. of moles of toulene solvent, = 5.4 mol

Hence, total number of moles of solution will be as follows.

                  n =

                     = 0.99 mol + 5.4 mol

                     = 6.39 mol

Therefore, mole fraction of cholestrol solute () is as follows.

                =  

      =

                      = 0.154

Vapor pressure of pure toulene solvent () = 41 torr

Vapor pressure of solution = P

Hence, formula to calculate relative lowering of vapor pressure is as follows.

     Relative lowering of vapor pressure =

As per relative lowering of vapor pressure colligative property, the relative lowering of vapor pressure is equal to the mole fraction of solute.

Hence,     =

                = 0.154

                         41 torr - P = 6.314

                                      P = 34.686 torr

or,                                      = 35 torr

Therefore, we can conclude that vapor pressure of the solution is 35 torr.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements