Comments re Chapter 6 Problems:
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6-2 |
Some T/F questions about chemical potentials. |
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6-25 |
Use data in a Table to calculate DGorxn, then compute Kpo and finally do the equilibrium problem by the method of successive approximations. The reaction itself is interesting. |
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6-32 |
An exercise that relates the magnitude of the equilibrium constant to the form of the balanced reaction. (Review of material from General Chemistry). |
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6-53 |
(Review of material from General Chemistry). |
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6-63 |
Another of Levine's thought problems. Very useful preparation for the multiple-choice questions on the hour exams. Most students would get the wrong answer for (d), which deals with a very fine (but interesting) point; part (d) is therefore optional. Parts (m) and (n) are also optional. |
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6-6 |
An exercise in determining whether or not a system is at equilibium with respect to a specific chemical reaction, i.e., the calculation and interpretation of the quantity Qp (same form as the equilibium constant but the gas pressures do not necessarily correspond to a set of equilibrium pressures). (Review of material from General Chemistry). |
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6-13 |
Exercise in extrapolating Kpo from one temperature to another. Note that DSorxn is given but is not needed for the calculation. |
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6-14 |
The value of Kpo is given as a mathematical function of T. Find DGo using the standard equation, find DHo and DCpo by taking the appropriate derivatives, and finally get DSo from DS = (DH - DG)/T. At the end calculate DHo at two temperatures. The two values differ, but only by less than 6%, so the assumption implicit in the usual equation for the variation in Kpo with T that DHo does not vary is reasonable. (The variation in DHo is small because DCpo is usually much smaller than DHo). Levine's notation "(T/K)", where K means units of Kelvin, can be confusing; it is probably easiest to just ignore all the factors "/K" and to remember that temperature must be given in degrees Kelvin. |
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6-15 |
(Calculation only). Shows how the temperature dependence of DHorxn affects the equation for the variation of the equilibrium constant with temperature. This derivation assumes that the Cpo values for all substances are independent of T, but remember that this assumption is less important than the assumption that DHorxn is independent of T. In any event DCpo changes only very slowly with T. This problem uses the same chemical reaction and the same temperature as problem 6-14, so comparisons are possible. Note that Kp values seldom have more than 2 significant digits; uncertainties of 20% or more are common. Please do not memorize this equation! |
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6-21 |
Short T/F exercise. |
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