Silberberg/Chemistry: The Molecular Nature of Matter and Change

Online Learning Center (Student) - SuperChallenge Problems

Chapter 1

1. At the Auric Arches Restaurant ("Billions and trillions of burgers served, several hundred actually eaten"), a "special sauce" is spread on all hamburger buns. How many buns, each of spreadable surface area 85 cm2, may be spread with 3.00 litres of sauce, if the thickness of the sauce is to be 250 pm?

2. Mozzarella cheese sells for $3.39 a pound (454 grams). The national debt of the United States is 6.2 T$. The density of mozzarella cheese is 0.87 g/mL. Calculate the national debt of the United States in cubic meters of mozzarella cheese. If this amount of mozzarella were in a single cube, how tall would the cube be? If the average pizza uses 6.0 ounces of mozarella as topping, how many pizzas could you top with this amount of mozarella?

3. Gold occurs in ocean water in a range of concentrations from 0.1 mg to 2 mg of gold per tonne of seawater. Near Iceland, the concentration is 1.5 mg of gold/ tonne of seawater.

How many tonnes of Icelandic seawater have to be processed to obtain 1.0 troy ounce of gold, if the recovery is 65% successful? One troy ounce, 31.1 grams, is the standard "ounce" in the gold trade.
If gold sells for $325/troy ounce, and the annual national budget of Iceland is $590 million, how many tonnes of Icelandic seawater have to be processed to obtain enough gold to pay Iceland's bills for a year, if the recovery is 65% successful?

4. During the time of the French Revolution (or some other such gallic excess), a metric clock was proposed. The length of a day was, of course, fixed to be the same length as now, but there was to be ten hours/day, exactly 100 minutes/hour, and exactly 100 seconds/minute. The idea never took hold, humans being so much more comfortable with the far more sensible idea of 2, 12 hour periods, and 60 minutes/hour, 60 seconds/minute.

a. Which is longer, a metric second of the proposed sort, or one of our "ordinary" seconds?

b. If your digital wristwatch reads "1:13:26.4 p. m.," what would be the reading on a metric watch at that time?

5. We’re going to construct a temperature scale, using you to set the points. Let the normal freezing point of water be the number of the month in which you were born. Add your age, in months, to that, to get the normal boiling point of water. What is a formula that relates your temperature scale to the Celsius scale? What would a thermometer in your scale read at zero Kelvins?

6. The "gauge" of a shotgun is defined in the following way: a pound of lead is melted into some number of identical spheres. If the result is 12 such identical spheres, and one just fits into the barrel of a shotgun, then that shotgun is "12 gauge," and so on for 10, 16, and 20 gauge shotguns. Consider the following: exactly one pound = 453.592 grams, and the density of lead is 11.344 g/cm3. From the definition of "gauge," and the information given, calculate the diameter, in mm, of the barrel of a "16 gauge" shotgun. For a sphere, V = 4/3 ?r3.

Class Term Projects

Explain any of the following to a bright, curious, eight year old child: atoms, molecules, ions, gas behavior, chemical bonding, chemical kinetics, entropy, why solutions are blue because they’re not red, or some other topic chosen in consultation with your instructor.

Compare atomic/molecular theory, stoichiometry, quantum mechanics, bonding, kinetics, equilibrium, kinetic-molecular theory, thermodynamics, and how each views matter and the changes it undergoes.
Compare biology, chemistry, and physics, and how each views matter and the changes it undergoes.

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