123 
An exercise in calculating vaporpressure lowering for a familiar solution. 
124 
A T/F problem on the subject of freezingpoint depression. Most of the questions (but not (c)) apply to the boilingpoint elevation as well. 
1213(b) 
An exercise involving the practical osmotic coefficient f, which multiplies the molality and accounts for nonideality (DT = K_{f}(m)(fn), where n is the number of ions per formula unit. The coefficient f itself is not so important; what is important is getting n correct for the solute and noticing that the solution is not ideal. What is the ratio of the measured freezingpoint depression to the expected depression? 
1214 
A problem in which the extent of dimerization of phenol (as measured by an equilibrium constant K_{x}) is determined from data about a freezingpoint depression. 
1215 
An unusual, but informative, problem involving a freezingpoint depression for a solution of two unreactive solutes. Rather than asking for a calculation of DT or molar mass or concentration, Levine asks about the relative amounts of the two solutes. 


1218 
Exercise in calculating osmotic pressure. In part (b) the calculated and observed osmotic pressures are compared to get a value for the activity coefficient of the solvent. For this part of the problem it is necessary to go back from the equation PV = n_{B}RT (or, C = n_{B}/V = P/RT) to the earlier equation ln(g_{A} X_{A}) = PV_{A}/RT (where V_{A} is the molar volume of A in solution and can be assumed to be the same as the molar volume of pure A). Note that the density of water is not quite 1.00 g/mL at 20° C. After getting V_{A} calculate X_{A} and solve for g_{A}. If g_{A} is not close to 1.00 something is wrong. 
1223 
Problem involving osmotic pressure and ionic strength. The equation is PV = n_{B}RT can be arranged to PV = (n_{B}/V)RT = CRT where C is the molarity of the solution. 
1228 
Very short exercise about the Gibbs Phase Rule. 
1235 
Please make the requested plot (a P vs. x diagram for the liquid and vapor
phases of an ideal binary solution) carefully, maybe using a
spreadsheet. (The word carefully means using either a
spreadsheet or a calculator and graph paper).
Draw the tie line that corresponds to a system that has a total
pressure of 40.0 torr 
1237 
A thought problem about twophase regions and tie lines. 
1266 
A thought problem that is based on a simple system in which the chemical potential of the solvent differs between two beakers because the solution concentrations are different. Since the liquid solvent is in equilibrium with its vapor, the solvent is constantly vaporizing and condensing. The solvent can therefore migrate from one beaker to the other. 
1272 
This question can be answered with a single sentence that requires no calculations or equations. Levine provides a slightly longer answer. 
1273 
Relates the four colligative properties. The hardest part of the problem is the conversion of molality to mole fraction. Remember that for water K_{b} = 0.513 °/m and that K_{f} = 1.86 °/m. The needed vapor pressure is given in the problem. 


1244 
Estimate the eutectic temperature and composition of a solution of benzene and cyclohexane by finding the intersection of the two freezingpoint depression curves. This is a good problem to do with a spreadsheet. The necessary equation is: ln(a_{A}/1) @ ln(X_{A}) @
(1/R)(D_{fus}H°)[(1/T_{fus,A})  (1/T_{fus,A}°)], 
1249 
A reasonably simple solidliquid phase diagram, but partial miscibility (solubility of A in B and B in A) must be considered. Note that neither the temperatures nor the compositions of the eutectics are given so it is just necessary to draw lines that look reasonable. 
1251 
Another solidliquid phase diagram. Several different compounds are present (each one is a line phase) but there are no complications from partial miscibility. 
1252 
Problem that emphasizes that the solubility of a solid in a liquid should depend only on the freezing point and heat of fusion of the solute. (The freezingpoint depression curve of a liquidsolid phase diagram is also a solubility curve because it gives the composition of the solution that is in equilibrium with the pure substance). For solutes and solvents that are chemically similar (so that the solutions are reasonably ideal) the solubilities predicted on the basis of the equation given above (see description of 12.44) are surprisingly accurate. 


1246 
Draw the phase diagram for the water – NaCl system (problem was done in class). 