Comments re Chapter 15 Problems:

15-1

Very short T/F question, but the distinction made is important.

15-2

A slightly longer T/F question.

15-3

How much translational energy does a gas have at 298 K?

15-5

Almost a thought problem.

15-6

A problem that is often done in General Chemistry courses.  Note that vrms is the root-mean-square speed, which means it is the square root of the average value of the squared speed.  (First the square, then the average, finally the square root).
Also, if PVm = RT = (2/3)Etrans,m = (2/3)[(1/2)Mráv2ñ], then vrms = áv2ñ1/2 = [3RT/Mr]1/2.

15-7

Another problem that could be done in a General Chemistry course.

 

 

15-15
(a only)

Calculation of the ratio of the distribution functions G(v) for v = 500 m/s and v = 1500 m/s if the gas is O2 at 25° C.  The speed may only increase by a factor of three, but the ratio of the probabilities drops precipitously.

15-20

Straightforward computation of rms, average, and most probable speeds for CO2(g) at 500 K.  The formulas can be found in the chapter (top of pg. 472);  it is not necessary to memorize them.  Please do, however, look at the values.

15-21

A somewhat messy derivation of a formula that turns out to be simple. What is needed is the right starting equation (15.44) and basic calculus. It is necessary to be careful taking the (somewhat complicated) derivative and to recognize that exponential functions can never equal 0 (unless the argument is negative and infinite). Don't worry about the normalization factor because it is a constant that cannot be zero.

15-29

Very short problem that makes an interesting point.

15-30

Another problem that could be given to good students in General Chemistry. Levine doesn't ask that the formula of the gas be determined, but doing so is not difficult.

15-40

How far do gas molecules travel between collisions (assuming a container large enough that collisions with the walls do not happen first)? A good exercise in cancelling units.

15-41

A problem based on the barometric formula.

15-42

The barometric formula applied to daily life. How much does the pressure fall per story of a standard building? (The answer, of course, is not very much.) This problem will be easier if an intermediate result for 15-41 is used.

15-55

One of Levine's thought problems.

 

 

15-46

An exercise in the prediction of a heat capacity. Look up Cp for CH4 at 298 K in Levine's Appendix and compare with the predicted value.

15-48

Calculation of the rms speed of a dust particle. Another good exercise in the cancelling of units.

15-60

Another one of Levine's thought problems.

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