Biphenyl, C12H10, is a nonvolatile, nonionizing solute that is soluble in benzene, C6H6. At 25 °C, the vapor pressure of pure benzene is 100.84 torr. What is the vapor pressure of a solution made from dissolving 17.3 g of biphenyl in 34.0 g of benzene?
mols biphenyl = grams/molar mass
mol benzene = grams/molar mass
Xbenzene = nbenzene/total mols.
Pbenzenesoln = Xbenzene*Pobenzene
To find the vapor pressure of the solution, we need to calculate the mole fraction of biphenyl in the solution and then use Raoult's Law.
1. Calculate the moles of biphenyl:
Moles of biphenyl = mass of biphenyl / molar mass of biphenyl
The molar mass of biphenyl (C12H10) can be calculated by adding the atomic masses of carbon (C) and hydrogen (H) atoms:
Molar mass of biphenyl = (12 * 12.01 g/mol) + (10 * 1.01 g/mol)
2. Calculate the moles of benzene:
Moles of benzene = mass of benzene / molar mass of benzene
The molar mass of benzene (C6H6) can be calculated by adding the atomic masses of carbon (C) and hydrogen (H) atoms:
Molar mass of benzene = (6 * 12.01 g/mol) + (6 * 1.01 g/mol)
3. Calculate the total moles of solute and solvent:
Total moles = moles of biphenyl + moles of benzene
4. Calculate the mole fraction of biphenyl:
Mole fraction of biphenyl = moles of biphenyl / total moles
5. Use Raoult's Law to calculate the vapor pressure of the solution:
Vapor pressure of solution = mole fraction of biphenyl * vapor pressure of pure benzene
6. Substitute the values into the equation to find the answer.
Note: Make sure to convert grams to moles using the molar mass and then proceed with the calculations.
Once you have completed the calculations, you will have the vapor pressure of the solution made from dissolving 17.3 g of biphenyl in 34.0 g of benzene at 25 °C.