Concept Test 8

Internet Concept Test Chemistry 22
Prof. J. C. Baird
Marn-Yee Lee, Silvia Georges, Derek Cummings
Topic: Entropy

A Question of Order and Disorder

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Up to 4 people can work together on this test.

There are 6 questions.

Background material. Why this is important and interesting. It is not necessary to read this.

As a friend of mine said when taking chemical thermodynamics at Stanford long ago, "entropy smentropy, what is entropy?" So here are five entropy questions.

Take black and white billard balls ordered in a box and shake it. What do you expect to happen? Which of the following two outcomes will be expected to occur?

Question 1

Reason for Answer:

Question 2

A cylinder, fitted with a crank attached to an inner cylinder, is filled with glycerol, a viscous fluid 900 times more viscous than water. Using a syringe filled with ink a vertical line is carefully injected into one side of the glycerine. The crank rotating the cylinder is turned a given number of revolutions.

The crank is now turned the same number of revolutions in the opposite direction. What do you expect to happen?

The crank is turned five revolutions counterclockwise and then five revolutions clockwise:

Reason for Answer:

Question 3

The box is shaken and there is an outcome. The crank is turned and unwound and there is another outcome. These results are:

Reason for Answer:

Professor Bisshopp has a dog named Trouble. Trouble has a certain number of fleas in each of the two situations as described below. These fleas jump from Trouble to her owner, Prof. Bisshopp, at some regular frequency (the jump time) and then back again in a random fashion. Imagine that the fleas are numbered and that the jumping occurs as a random number is drawn. The flea whose number is drawn jumps to the other being (i.e., from Bisshopp to Trouble or from Trouble to Bisshopp.).

In the description above the number of fleas represents the concentration of molecules in a chemical reaction. The reaction begins with all the molecules as reactants and proceeds in time creating product molecules (fleas on Fred Bisshopp) until equilibrium is reached. In this formulation the equilibrium constant is K = 1. The answer may be understood by running a program for the Macintosh called DogFlea.hqx found by clicking here.

Question 4

If Trouble starts out with 5 fleas there is a good chance that after some time that the

Reason for Answer:

Question 5

If Trouble starts out with 200 fleas there is a good chance that after some time the

Reason for Answer:

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