Chem 3433-63342, Physical Chemistry 1
When possible, use the values for constants from our text. If you get them from other sources (if they are not in the book) cite where you got them from.
- (10 pts) Phase diagram
Uranium tetrafluoride (Tm = 1035 °C) and zirconium tetrafluoride (Tm = 912 °C) form a continuous phase of a solid solution with a minimum melting temperature of 765 °C at X(ZrF4) = 0.77. At 900 °C, the liquid solution with X(ZrF4) = 0.28 is in equilibrium with a solid solution with X(ZrF4) = 0.14. Also, the solution with X(ZrF4) = 0.87 is in equilibrium with X(ZrF4) = 0.90.
Based on this information, sketch the phase diagram. Explain what happens if a solution at X(ZrF4) = 0.10 and 1050 °C was cooled slowly to 800 °C. At 975 °C and X(ZrF4) = 0.10, how many phases are there , what are their compositions and what are the their relative amounts?
- (10 pts) Boiling point or FP problem.
M&S, P25.41 (please try not to look at the answer in the book.)
- (10 pts) Osmotic pressure estimate for polymer.
The osmotic pressure of polymer solutions were measured at 30 °C to be:
c (mg/mL) 1.33 2.10 4.52 7.18 9.87
π (N/m-2) 30 51 132 246 390
The densities of the polymer and solvent (toluene) were: 1.25 and 0.858 g/cm3, respectively. Estimate the molecular mass of the polymer and the second virial coefficient. Remember the plot can be a straight line or curved and may take either a linear or 2nd order fit.
- (10 pts) Activity coefficient
Calculate the activity coefficient, g+/- for aqueous KCl for A) 0.02 m KCl and B) a mixture of 0.02 m KCl in solution with 0.02 m Na2CO3. m = moles/kg solvent. Why are they different or the same?