Problems to Accompany

Braving the Elements

Harry Gray, John Simon & William Trogler

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Problems for Chapter 1

1) Helium is produced constantly in the earth's crust as a product of radioactive decay. Although helium gas is unreactive, and it escapes from the earth's crust, its fraction in the atmosphere is very low (5 parts helium in 1 million parts of air) and constant. Suggest a reason for why the helium constantly being added to the earth's atmosphere doesn't accumulate.

 

2) The earth's atmosphere consists predominantly of nitrogen and oxygen. None the less, deep sea divers breathe a helium/oxygen gas mixture. Why is helium, a more expensive gas, used in place of nitrogen?

 

3) The fraction of carbon dioxide gas is uniform in the earth's atmosphere, but that of water vapor, often given as percent humidity, is not. What difference in the physical properties of CO2 and H2O accounts of the contrasting behavior?

 

4) What elements do the following substances have in common?

a) wood, gasoline, human skin, table sugar, and sandwich bags

b) rubies, opals, sapphire, clay, and porcelain

c) sand, glass, quartz, solar cells, and computer chips

d) laughing gas, ammonia fertilizer, nitroglycerin, and the earth's atmosphere

 

5) Research one element in the periodic table, and write a paragraph that describes its uses.

 

6) List the elements added to the vitamin tablets in the multivitamin-mineral supplements found in your local pharmacy. Do you find differences among commercial brands?

 

7) Pick an element named after a scientist and write a paragraph about his or her contribution to science.

 

8) If the next element discovered were to be named after a living scientist who would you choose (please exclude the course instructor) and why?

 

9) a) Why are metals used in cookware?

b) Why are metals used in electrical wires?

c) Which exhibits greater mobility in metals, electrons or nuclei.

Why?

 

10) A mole of water has a mass of 18 grams. A liter of liquid water weighs 1000 grams.

a) How many moles of water are contained in a liter of the liquid?

b) The human body contains about 6 liters of blood. About how

many moles of water are there in your circulatory system?

c) About how many molecules of water are there in the circulatory

system?

 

Problems for Chapter 2

1) What is the lightest element that can exhibit radioactivity?

 

2) What is the lightest naturally occurring element on earth that is radioactive?

 

3) In the 1940's what was the mission of the U.S. government laboratory built at Hanford, WA?

 

4) What scientific contribution did the following scientists make pertaining to radioactivity?

a) Henri Becquerel

b) Marie Curie

c) Enrico Fermi

d) Otto Hahn

e) Glenn Seaborg

f) Rosalyn Yalow

 

5) What are some uses of the following radioactive elements?

a) 32P

b) 99mTc

c) 60Co

d) 131I

e) 11C

 

6) Why is there an international treaty that bans above ground testing of nuclear weapons? Be specific.

 

7) Which of the following countries provides the greatest fraction of its electrical power from nuclear reactors? Which provides the least?

China, Germany, Great Britain, France, Japan, Russia, The United States

8) Why is liquid sodium used to cool some nuclear reactors? Do you think this is safer or more dangerous than using high pressure water as a coolant? Why?

 

9) What are the advantages and disadvantages of using nuclear powered space craft?

 

10) Does nuclear magnetic resonance imaging, commonly called MRI, pose a radiation hazard to the patient?

 

11) Why are heavy elements rare in nature?

 

12) Our sun "burns" hydrogen as an energy source. In what state, does the hydrogen exist?

 

13) Radon is a member of the unreactive family of noble gases in the periodic table, and it is produced naturally in the Earth's crust by radioactive decay. Unlike helium, neon, argon, and xenon, radon is carcinogenic. Suggest a reason for this.

 

Problems for Chapter 3

1) The New Zealand born scientist, Ernest Rutherford, earned the 1908 Nobel Prize in chemistry for his work on radioactive decay paths of the elements. In addition, he trained eleven students or coworkers, who later received Nobel Prizes in chemistry or physics. List his coworkers and the subject of their prize-winning research.

 

2) Why is it important to have a small percentage of carbon in steel?

 

3 An important consideration in the use of alloys is their density, which is the mass of a given volume of metal. The density of iron is 7.86 kg/liter, magnesium is 1.74 kg/liter, aluminum is 2.70 kg/liter, titanium is 4.51 kg/liter, lead is 11.34 kg/liter, and uranium is 19.05 kg/liter. On the earth's surface a liter volume of the above metals would weigh 17.3, 3.8, 6.0, 9.9, 25.0, and 42.0 lbs, respectively. Discuss examples where the relative weights are important to the uses of these metals. Can you suggest a reason why uranium metal finds use in armor piercing anti-tank projectiles?.

 

4) Which metals used in dental amalgam are toxic if solubilized?

 

5) Some varnish and paint removers contain methylene chloride or dichloromethane (CH2Cl2) as a major liquid component. What role might it serve?

 

6) With the rule that carbon normally forms four bonds and hydrogen one, suggest all possible structures for molecules with the formula.

a) C3H8

b) C3H6

c) C3H4

 

7) Can you explain why paper plates don't heat up in a microwave oven?

 

8) Squeeze the essence from the outer surface of an orange peel onto the surface of a styrofoam cup. Styrofoam is a foam made from hydrocarbon molecules. What happens to the cup when the material from the orange peel drips onto the polystyrene? What does this suggest about the liquid chemical in the orange peel.

 

9) Consider the reactions between methane and oxygen to form carbon dioxide and water. Write the net reaction. List the bonds that are broken in the reactants and those that form in the products.

 

10) Chemical bonds generally form so that a molecule adopts a rigid shape around each atom, but rotation may freely occur around single bonds. Whenever four bonds form to carbon they always are arranged around carbon in a tetrahedral geometry. What do these facts imply about the structure and flexibility in the ethane molecule, C2H6?

 

Problems for Chapter 4

1) Describe the physical symptoms that accompany a deficiency of Vitamin C and vitamin E.

 

2) Look in metropolitan newspaper and compare the reported concentrations of ozone and carbon monoxide with those found on the same day (use library) in Los Angeles and London.

 

3) Humans need oxygen to breathe; however, a pure oxygen atmosphere is toxic? Why?

 

4) What explosive was used in the New York Trade Center bombing of 1993 and in the Oklahoma City Federal Office bombing of 1995?

 

5) What antibiotic ointments are available in over the counter medications for treating skin cuts? Find chemical structures in the Merck Index.

 

6) Make a table and compare the chemical composition of five or more cold remedies at your pharmacy. Identify the role of the various components (e.g., antihistamine, decongestant, anticough, expectorant, antipyretic). Discuss the differences and similarities. Is there any correlation between the ingredients, their amounts, and the cost of the various medications?

 

7) It is likely that an increased greenhouse effect on Earth will accelerate plant growth. Suggest a reason for this that is unrelated to temperature.

 

8) How do cocaine and heroin differ in their physiological effects?

 

9) Order the following recipes by the amount of fat in the final loaf of bread.

Portuguese White Bread - 1 cup water, 3 tbs margarine, 1 tbs sugar, 1 tsp salt, 2 3/4 cups flour, 1 package yeast.

Italian Bread - 1 cup water, 3/4 tsp salt, 2/3 cup sugar, 2 cups flour, 1 package of yeast.

French Bread - 3/4 cups water, 2 1/2 tsp sugar, 2 tsp olive oil, 2/3 tsp salt, 2 cups flour, 1 package of yeast.

 

10) The first example of a chemically induced cancer stemmed from the observation that chimney sweeps suffered an abnormally high incidence of certain skin cancers. What occupational chemical was the cause of this?

 

11) Are all cancers caused by chemicals?

 

12) What chemical compound is used for:

a) the fizz in soft drinks

b) a solvent under high pressure to decaffeinated coffee

c) making dry ice

d) a propellant in spray cans

e) making bread rise

 

13) Less than one-percent of the 9 million deaths in World War I were caused by chemical warfare agents. These causalities were primarily military. For comparison, more civilians perished in a single night's fire-bombing of Hamburg or Tokyo during World War II. Fire bombing was a strategy developed by the Allies. An initial wave of bombers used high explosives to demolish buildings and homes, which spread readily ignited debris. A following wave of incendiary bombs then created a firestorm. Hurricane force winds were produced as the hot air rose, and this caused fresh air to race in at ground level and fan the flames. In The Making of the Atomic Bomb, author Richard Rhodes recounts a story by a 19-year old survivor of the fire-bombing of Hamburg.

"We got to the L÷schplatz [park] all right but I couldn't go on across the Eiffestrasse because the asphalt had melted. There were people on the roadway, some already dead, some still lying alive but stuck in the asphalt. They must have rushed on to the roadway without thinking. Their feet had got stuck and then they had put out their hands to try to get out again. They were on their hands and knees screaming."

Some argue that treaties, which ban chemical weapons, are humane gestures that make war more civilized. Others contend that chemical weapons are no less brutal than the other techniques used in war. Do treaties to ban chemical weapons detract attention from the central issue? Write an essay about your view on treaties that ban weapons selectively. Do you think they help deter war or make war a more palatable option?

 

14) What is the chemical structure of the drug Prozac« (fluoxetine)? What is its use?

 

Problems for Chapter 5

1) Why is it important to have a small percentage of carbon in steel?

 

2) An important consideration in the use of alloys is their density, which is the mass of a given volume of metal. The density of iron is 7.86 kg/liter, magnesium is 1.74 kg/liter, 2.70 kg/liter, titanium is 4.51 kg/liter, lead is 11.34 kg/liter, and uranium is 19.05 kg/liter. On the earth's surface a liter of the above metals would weigh 17.3, 3.8, 6.0, 9.9, 25.0, and 42.0 lbs, respectively. Discuss examples where the relative weights are important to the use of the metals. Does the data suggest a reason why uranium metal finds use in armor piercing anti-tank projectiles?.

 

3) Which of the metals used in dental amalgam are toxic if solubilized?

 

4) Some varnish and paint removers often contain methylene chloride or dichloromethane, CH2Cl2 as a major liquid component. What role might it serve?

 

5) In gas fired hot water heaters a drip-hiss, drip-hiss, ... noise can often be noticed when the burner first ignites. Why does this occur?

 

6) Look at the chemical additives to three or four packaged bakery products and find out (library) why they were added.

 

7) Which is a better dietary drink, soda pop or beer?

 

8) In metallized solid rocket fuel, finely divided aluminum is added to enhance heat generation. Iron metal could be used instead to generate heat, but aluminum is preferred. Why?

 

9) Discuss some of the reasons why the common flashlight battery might lose its charge when it is stored for a long period of time, or placed in a hot environment.

 

10) Use litmus paper, which turns red in acidic solution and blue in basic solution, to determine the acidity of some foods, liquids, and moist surfaces around the home. Test the pH of your tap water. Obtain some soil from a nearby garden or lawn area, shake it with a small amount of water, let it settle, and then test the acidity of the water above the solids. Report your findings.

 

11) Take some baking soda from your kitchen and dissolve it in some warm water in large glass. Add a couple drops of a liquid dish soap and stir. Now pour vinegar into this solution. Describe what happens and the chemical reaction involved.

 

12) Classify the following chemical reactions as acid-base or oxidation-reduction. Identify the acid and base, or oxidant and reductant for each case.

a) The Hindenburg explosion.

b) The rusting of iron.

c) The rising of a pancake.

d) The burning of gasoline in an automobile.

 

Problems for Chapter 6

1) Make a list of the five most beneficial chemicals in your own life, and a list of the five chemicals you fear or detest most.

 

2) Describe how one of the mineral sources of an element in Table 2 is treated to make the pure element, and two uses of the element.

 

3) Describe what role Fritz Haber played in industrial chemistry and chemical warfare.

 

4) Compare the relative heats of combustion in Table 2 of Chapter 5 for gasoline, ethanol, and methanol.

a) Ethanol is commonly added (5-10%) to gasoline to make gasohol. Would you expect your gas mileage to increase or decrease if you use gasohol instead of straight gasoline?

b) Methanol has been proposed as a fuel of the future for automobiles. Current automotive engines can run on methanol with relatively minor modifications. By what percent would you have to change the size of the gas tank, if you wanted a car to have the same maximum range per tank.

c) Look up the proposed advantages for the potential use of methanol as a fuel. Based on your readings, would you support a government program to switch to methanol as a fuel? List the scientific, environmental, and economic issues that influenced your decision.

 

5) What chemical or biochemical industries are near where you live? What do they manufacture?

 

6) Look up the current price per ounce of gold, silver, platinum, and rhodium. List an industrial (i.e. non jewelry) use for each element.

 

7) What is the Superfund tax on industry?

 

8) Look up the following major chemical companies on the New York Stock Exchange: Dow Chemical, DuPont, Union Carbide, Monsanto, and Eastman Kodak.

a) Does their current price compared to their 52 week high and low indicate a rise or decline in value?

b) Does their value reflect the general sentiment (recovery vs. recession) for the general economy, as expected for a cyclical stock.

c) Do you feel they are sound long term investments?

 

9) Look up the following drug-biotechnology companies: Merck, Pfizer, Genentech, Schering-Plough, and Amgen.

a) How do these investments compare to those in problem #8 in terms of stability and long term growth?

b) Are there any differences in the P/E (price to earnings) ratios in comparison to chemical companies. If so, then what might be the reason for the difference?

c) Submit a $10,000 investment portfolio spread over the stocks of the preceding 10 companies in any distribution you like. Calculate the worth of your portfolio and hand it in on the last day of class. Did any significant events during the term effect your investment?

 

10) What major natural mineral resources are located within 100 miles of the area you live? What is their end use?

 

11) Describe some of the important natural components in crude oil.

 

12) What are some of the chemical processes carried out in oil refineries? What economic purpose do they serve?

 

13) What are the three main elements chemical fertilizers provide. List three compounds commonly used in bulk fertilizers.

 

Problems for Chapter 7

1) What is "vinyl" floor tile made from?

2) What is the difference between "acrylic latex" (used in paints and caulking) and latex rubber?

3) List five natural polymers.

4) What is rayon? How is it made?

5) How is the glass for optical fibers made? How is it processed into fibers?

6) What ceramic is used to make the heat shield tiles on the space shuttle? Why do they sometimes fall off?

7) Tabulate the different synthetic fibers used in articles of clothing you own.

8) What are four potential uses for high-temperature super conducting materials?

9) Why have graphite, boron, and Kevlar« composite tennis racquets and golf clubs replaced the older metal versions? Can you envision any problems with a bicycle frame made of one of the composite materials?

10) What was the first "high temperature superconductor", and what was the maximum temperature at which it was superconducting. What is the best high temperature superconductor today, and what is the maximum temperature at which it superconducts?

 

11) What would be the structure of the addition polymer made from the following monomer?

Acrylamide is often polymerized in a water solution to prepare a wetted gel for the separation of proteins. In this technique, an electric field is applied across a plate of the gel, which is spotted with a protein mixture at one end. The various protein components migrate across the gel plate at different speeds. The separated proteins can then be stained and visualized. The technique is called gel electrophoresis.

 

12) List two ceramics and their uses.

 

13) How is colored glass made?

 

Problems for Chapter 8

1) a) Describe genetic engineering in your own words.

b) What are some moral concerns about research in genetic engineering?

c) What are the potential benefits and hazards of this research?

 

2) Research has shown that the protein cytochrome c involved in metabolism in organisms from bacteria to humans share large regions of identical amino acid sequence.

a) Do you think this supports a common origin of life?

b) Do you think it supports the theory of evolution?

 

3) a) Would you be missing any essential amino acids if you tried to exist on a diet that consisted only of water and pasta made from wheat? If so, then what one or two foods would you add to make it an adequate subsistence diet?

b) Some poor regions of the Far East suffer from fatal episodes when rice constitutes the primary food source for extended periods. Explain.

 

4) What difference in the eye's radiation detectors causes color blindness?

 

5) Describe exactly how the anticancer drug, Cisplatin«, was discovered.

 

6) What is the biochemical origin of menopause in women? Can the symptoms be alleviated with drugs?

 

7) Where are the following elements found in the body?

a) iron

b) iodine

c) calcium

d) nickel

 

8) What is MSG? Is it related to any of the amino acids in this chapter? Why are some people sensitive to it, as in "Chinese restaurant syndrome." Soy sauce is a solution of salt and hydrolyzed (broken down into smaller proteins and amino acids) soy protein. People sensitive to MSG also are sensitive to soy sauce as well. Suggest a reason for this.

 

9) What is a gene, in chemical terms?

 

10) The nitrogen mustard class of anticancer drugs were the first to be investigated. One still in use as a palliative treatment for advanced cancer is called Mustargen« (methchlorethamine HCl, a nitrogen analog of mustard gas.

When the compound enters the cell, the two reactive chlorine atoms in the compound are replaced and a bonds form to a nitrogen atom on two different DNA bases. It is called a difunctional alkylating agent and it inhibits growth of rapidly proliferating cells. The analogous compound that contains only one reactive chlorine, a monofunctional alkylating agent, is ineffective as an anticancer drug. Suggest a reason why the difunctionality might inhibit DNA replication.

 

11) Looking at the X-ray structure of myoglobin or hemoglobin, the iron that binds O2 is completely surrounded by the protein. On the surfaces of these proteins there are no openings big enough for the O2 molecule to gain access to the iron binding sites. Yet in the human body, oxygen easily attaches and releases from the binding sites. Propose an explanation.

 

12) What gives hair its color, and what happens when it turns gray?

 

Problems for Chapter 9

1) Explain why radio waves can go through the walls of your house, but why light waves cannot.

 

2) Why might the U. S. Navy be interested in a blue-green laser for satellite to submarine optical communications?

 

3) Why are most industrial chemical processes thermal, instead of photochemical?

 

4) Some 100 kilometers or more above the earth's surface lies a region of the atmosphere called the ionosphere. The pressure of gases here is less than 1 millionth that at the earth's surface, and molecules collide infrequently. The ionosphere gets its name from the unusually large number of ions present. High energy ultraviolet and low energy X-rays from the sun enter this region of the atmosphere and are absorbed by O2 and N2 to produce oxygen and nitrogen atoms. These atoms can further absorb high energy radiation and undergo ionization as follows:

O + hn —> O+ + e-

N + hn —> N+ + e-

Charged particles, such as protons in the solar wind, can also cause ionization when they collide with atoms in the ionosphere. The earth's magnetic field deflects the approaching charged particles, so this effect is especially pronounced at the polar regions of the earth. Radio waves are reflected by the ionosphere, and this permits transmission around the curvature of the earth.

Although collisions are infrequent in the ionosphere, some recombination of ions does occur. One responsible for the main color observed in the aurora borealis or northern lights, is:

O+ + e- —> O*

The excited oxygen atom produced, O*, can emit a photon at 560 nm. What color would this appear to a human?

 

5) List three civilian or military applications of infrared radiation.

 

6) What part of the solar spectrum causes:

a) Fading of colored paint.

b) Sunburn

c) Photosynthesis

d) Ozone production in the stratosphere

 

7) An average car requires about 100 kilowatts to run. How big (in square meters) a solar collector would you need to mount on top of a conventional automobile to generate equivalent power. Assume you could capture solar radiation with 80% efficiency? Is this practical with standard technology?

 

8) Why do people in tropical climates often wear white clothing?

 

9) a) Explain how a negative image is converted into a normal photographic image.

b) Explain why the use of a red filter on a camera makes clouds stand out better in a black and white photograph.

 

10) a) How long would it take for light to travel from the earth to the moon?

b) How long would it take a radio signal to go from the earth to the moon?

 

11) The UV light absorbing power of sun-screens is given by the skin protection factor (SPF). What is it? What are the UV A and UV B regions? To which does the SPF apply? Look at some sun-screens in your local pharmacy. Do any protect against both UV A and B?

 

12) What causes the difference in color of silver and gold metal?

 

13) Nocturnal animals (e.g., cats) eyes stand out in the dark because the back of their eyes are coated with a reflective coating. What purpose does this serve?

 

Problems for Chapter 10

 

1) What evidence suggests that the Antarctic ozone hole arises from the presence of CFCs in the stratosphere?

 

2) About how long would it take to restore the loss in stratospheric ozone by rapid world wide government action?

 

3) Why is the loss of stratospheric ozone greatest over the Antarctic?

 

4) One effect of Antarctic ozone depletion is a decrease in phytoplankton growth in the Southern Hemispheric oceans. Is there a reason why this might be a cause for concern?

 

5) Propose a practical world wide strategy to combat global warming.

 

6) Explain how ozone forms as a pollutant in the atmosphere of cities.

 

7) Emission controls for automobiles focus on minimizing the amount of unburned volatile organic compounds (VOCs), NOx (primarily NO), and toxic carbon monoxide (CO). Explain why some air is injected into the exhaust gases before they are passed over a catalytic converter.

 

8) Explain the chemical role that natural limestone minerals play in the problem of acid rain.

 

9) Recent measurements suggest that the reduction of sulfur oxide emissions from coal-fired power plants in the midwest and northeast regions of the U.S. have not reduced the acidity of precipitation as much as predicted, even though the amount of sulfate in rainwater has decreased significantly. At the same time, the acidity of lakes and streams in the northeast continues to increase slightly. Suggest two possible explanations for these observations.

 

10) Sulfur dioxide emission credits are sold by the government in biyearly auctions. The Chicago Board of Trade deals in the allowances, which trade on the open market. Each allowance permits an industry to emit one ton of sulfur dioxide per year above the restrictions mandated by the 1990 Clean Air Act. At the first auction, held in 1993, the 150,000 allowances sold at prices between $122 and $450. This provides a mechanism for one industry to exceed restricted emissions by purchasing allowances. This market-based pricing concept has been adopted by California's South Coast Air Quality Management District by setting an annual limit on the total amount of air pollution a factory can emit during the year. Companies that reduce their emissions below their annual limits can sell their credits to others unable to meet their targets.

Write an essay giving reasons whether you favor or disfavor the creation of a market for pollution allowances.

 

11) Find the EPA's Toxic Release Inventory in a major public or university library. Provide an example of one industry in your geographic location that emits a significant amount of a toxic compound to the environment.

 

12) Write a paragraph explaining why you think that advances in science and technology might or might not eventually solve air pollution problems, such as ozone depletion and greenhouse gas emissions?

 

13) Keep an hourly diary for one day on how your activities contributed to air pollution. In retrospect, what might you have done to avoid or minimize your adverse environmental impact?

 

Problems for Chapter 11

1) Some estimate that the use of $1 of pesticides and herbicides increases agricultural productivity by $4. Assuming this estimate is valid, would you be willing to ban the use of pesticides and herbicides and pay about four times as much for fruits and vegetables, or do you feel comfortable with present risks? Explain your reasoning.

 

2) Describe the debate arising over the Delaney clause and the food supply. Would you favor a negligible risk standard instead?

 

3) Do you think the one in a million cancer risk standard used to estimate safe levels for environmental lifetime exposure to possible carcinogens is sensible? Give reasons.

 

4) Describe the new findings about the human health hazards of dioxin that have been discovered since this book was written.

 

5) Give reasons why you favor or disfavor the selling of undiluted pesticides and herbicides for homeowner use. Would you go as far as requiring one to obtain a license and training for the application of toxic substances?

 

6) List the major benefits obtained in the use of DDT and the major drawbacks.

 

7) Research and describe the most exciting anticancer drug currently making headlines in the popular press. Provide its chemical structure and proposed mode of action.

 

8) Describe the two general ways radiation is currently used to treat cancer.

 

9) Why do many chemotherapy drugs cause hair loss?

 

10) Give specific examples where the information in this course has been useful to you. Were there any topics you would have like to seen included that weren't?