mols biphenyl = grams/molar mass.
mols benzene = grams/molar mass
Xbenzene = mols benzene/total mols.
pbenzene soln = Xbenzene*Ppure benzene solvent.
mols benzene = grams/molar mass
Xbenzene = mols benzene/total mols.
pbenzene soln = Xbenzene*Ppure benzene solvent.
First, let's calculate the number of moles of biphenyl and benzene in the solution.
The molar mass of biphenyl (C12H10) is:
12 * 12.01 (carbon) + 10 * 1.01 (hydrogen) = 154.22 g/mol.
To find the moles of biphenyl:
moles of biphenyl = mass of biphenyl / molar mass of biphenyl
moles of biphenyl = 19.9 g / 154.22 g/mol
Next, we calculate the moles of benzene:
molar mass of benzene (C6H6) = 6 * 12.01 (carbon) + 6 * 1.01 (hydrogen) = 78.11 g/mol
moles of benzene = mass of benzene / molar mass of benzene
moles of benzene = 34.3 g / 78.11 g/mol
Now, we can calculate the mole fraction of benzene:
mole fraction of benzene = moles of benzene / (moles of biphenyl + moles of benzene)
Next, we need to find the vapor pressure of the pure benzene (P°benzene), which is given as 100.84 torr.
Finally, we can use Raoult's Law to find the vapor pressure of the solution (Psolution):
Psolution = mole fraction of benzene * P°benzene
So, by plugging in the known values, we can find the answer.