Chemistry Everyday for Everyone
What Is It Used for? A Consumer-Chemical Hunt
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Arthur M. Last Department of Chemistry, University College of the Fraser Valley, Abbotsford, BC V2S 7M9, Canada;
[email protected] One of the activities that I organized as part of our college’s 1996 National Chemistry Week (NCW) celebrations was a scavenger hunt in which students were invited to find certain chemistry-related items and chemical information— bank notes and postage stamps pertaining to chemistry, chemistry-related cartoons, consumer items containing specific chemicals, facts about well-known chemists, etc. (1, 2) In addition to providing students with an activity that was entertaining and enjoyable, one of the objectives of the contest was to illustrate the important role played by chemicals in our modern consumer-oriented society. With this latter goal in mind, for one of our 1997 NCW activities I developed the consumer-chemical hunt described in this article. In this hunt, competitors were provided with information about a number of chemical compounds and had one week in which to determine the identity of each compound and to find one consumer product (identified by brand name in order to facilitate verification) in which each chemical is an important ingredient. Many of the relevant products can be found on the shelves of supermarkets or drugstores; locating others necessitates a trip to a hardware store or garden center. Of course, some students are able to find a significant proportion of the products in their own homes. This contest could also be used as an informal end-ofsemester activity, or as an assignment in a course where the focus is on the role of chemistry in society. As it stands, the contest is best suited for freshman and sophomore students at a college or university, but it could be modified for use by pre-college students. To encourage participation, we offered a prize of a $50 gift certificate, redeemable at the college bookstore, to the winner in each of the following categories: firstyear students, second-year students, and prep-chem students. To encourage participation by students of all abilities in each category, a number of smaller prizes (NCW caps and teeshirts, movie passes, etc.) were randomly awarded by drawing names from all the entries received. Follow-Up Activities Shortly after the winners of the competition were announced, selected consumer products containing the chemicals featured in the hunt were arranged in a display cabinet just outside our undergraduate laboratories. Accompanying posters provided additional information on some of the products— details of their manufacture, etc. Molecular models of the more complex organic compounds were also displayed. In addition to providing contestants with a list of acceptable solutions, this display proved to be of interest to many individuals who were not involved in chemistry. Contest DetailsW,1 Use the information given to identify each of the substances described below, and for each substance identify one consumer product in which the substance is an ingredient. Compounds may be identified by their IUPAC name, common
name, or formula. Whenever possible, consumer products should be identified by brand name. Two points will be awarded for each question: one point for the correctly identified substance and one point for an appropriate consumer product. In some cases more than one compound will satisfy the description provided; however, contestants should only list one compound, as no extra points will be awarded if two or more compounds are listed. In the event that two contestants competing in the same category finish with equal scores, the winner will be determined by a 24-hour tie-breaker. Numerical data for items 1 and 12 were obtained from the 76th edition of the CRC Handbook of Chemistry and Physics (3). 1. An insoluble group 2 metal salt with a K sp of 4.96 × 10{9 at 25 °C. 2. A tribasic inorganic acid. 3. A heptahydrate salt of the element whose nucleus contains 12 protons. 4. An ionic compound with isoelectronic anions and cations. 5. A salt that imparts a yellow color to a Bunsen flame in the so-called “flame test”, and that reacts with silver nitrate solution to give a precipitate that is soluble in both aqueous ammonia and nitric acid. 6. A compound in which chlorine is in the +1 oxidation state. 7. An inorganic compound containing an oxygen–oxygen single bond. 8. A compound that would release a basic gas when it is heated with aqueous sodium hydroxide, and would give a precipitate when added to aqueous barium chloride. 9. A binary ionic compound formed between the element with the lowest first ionization potential in period 4 of the periodic table and the element with the most negative electron affinity in period 5. 10. A hydrated salt containing a divalent transition-metal ion with six 3d electrons. 11. An acid salt. 12. An organic acid whose pKa is 4.76 at 25 °C. 13. A tribasic organic acid. 14. A compound that gives acetone when it is oxidized with acidic sodium or potassium dichromate. 15. The organic product obtained when ethene is reacted with dilute potassium permanganate. 16. An organic compound containing an oxygen–oxygen single bond. 17. BHT. 18. An aromatic compound that is both a phenol and a carboxylic acid. 19. The product of reacting the compound in Question 18 with acetic anhydride. 20. α-D-Glucopyranosyl-β-D-fructofuranoside 21. LDPE 22. HDPE
JChemEd.chem.wisc.edu • Vol. 76 No. 11 November 1999 • Journal of Chemical Education
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Chemistry Everyday for Everyone 23. PET 24. A compound containing a chiral carbon atom to which is attached a hydrogen atom, a methyl group, a carboxyl group, and a benzene ring substituted in the para position with an isobutyl group. 25. An aromatic compound with a molar mass of 147.01 g?mol{1 and the following percentage composition (by mass): carbon 49.02%, hydrogen 2.74%, chlorine 48.23%.
Acceptable Solutions2 1. Calcium carbonate; antacids, e.g., Tums, Rolaids. Also present in some calcium supplements. 2. Phosphoric acid; Coca Cola. Boric acid; Optrex eye drops. Pure boric acid is also sold for use as a mild antiseptic. 3. Magnesium sulfate heptahydrate, MgSO4?7H2O; sold as Epsom salts for use as a laxative. Also sold in garden centers under its chemical name for use as a source of magnesium for plants. 4. Sodium fluoride; toothpaste, e.g., Crest. 5. Sodium phosphate; sold as trisodium phosphate or TSP and used as a cleaning agent. 6. Sodium hypochlorite; bleach, e.g., Javex. 7. Hydrogen peroxide; sold as an antiseptic (3% solution), hair bleach (6% solution). Many drugstores and supermarkets sell their own brands. A 35% solution is often available in garden centers. 8. Ammonium sulfate; sold under its chemical name in garden centers for use as a nitrogen-rich fertilizer. 9. Potassium iodide; present in “iodized” table salt, e.g., Sifto Table Salt. 10. Iron(II) sulfate monohydrate, FeSO4?H2O; sold under its chemical name in garden centers to add green color to plant leaves. 11. Sodium bicarbonate; baking soda, e.g., Arm and Hammer. Ammonium bicarbonate; food additive, e.g., Honey Maid Graham Crumbs. Sodium bisulfite; food preservative (antioxidant), e.g., Realemon lemon juice concentrate. Monosodium glutamate (MSG); a widely used flavor enhancer. 12. Acetic acid, or ethanoic acid; all brands of vinegar. 13. Citric acid; soft drinks, e.g., Canada Dry Ginger Ale, Sprite; candy, e.g., Lifesavers; many brands of chocolates. Citric acid is also sold in pure form. 14. Isopropyl alcohol, or 2-propanol; rubbing alcohol. Many drugstores and supermarkets sell their own brand of rubbing alcohol. 15. Ethylene glycol, or 1,2-ethanediol; radiator antifreeze, e.g., Prestone. 16. Benzoyl peroxide; acne treatments, e.g., Benzagel Acne Gel. 17. Butylated hydroxytoluene, or 2,6-di-t-butyl-4-
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18. 19. 20. 21. 22. 23. 24.
25.
methylphenol; present in foods or food packaging as an antioxidant, e.g., the breakfast cereal Presidents Choice Crispy Rice. Salicylic acid, or 2-hydroxybenzoic acid, or 2hydroxybenzenecarboxylic acid; Acne treatments, e.g., Oxy Power Pads; wart remover, e.g., Compound W. Acetylsalicylic acid or 2-(acetyloxy)benzoic acid, or 2ethanoyloxybenzenecarboxylic acid; analgesics, e.g., Aspirin. Sucrose; sugar. Low density polyethylene; plastic supermarket bags. High density polyethylene; 4-L plastic milk jugs, bleach bottles, etc. Poly(ethylene terephthalate); 2-L pop bottles. Ibuprofen, or 2-(4-isobutylphenyl)propanoic acid, or α-methyl-4-(2- methylpropyl)benzeneacetic acid, or p-isobutylhydratropic acid; analgesics, e.g., Advil. 1,4-Dichlorobenzene or para-dichlorobenzene; moth repellent, deodorizers e.g., Parazene Closet Freshener.
Possible Tie-Breakers 1. The amphoteric oxide of a d-block element. Solution: Zinc oxide; present in many medicated ointments, e.g., Penaten Cream, used extensively for treating diaper rash. 2. The compound that is produced by the following three-step synthesis: (i) reaction of phenol with a mixture of nitric and sulfuric acids, (ii) reaction of the product from (i) with iron and acetic acid, and (iii) reaction of the product of (ii) with acetic anhydride. Solution: Acetaminophen, or 4-acetamidophenol, N(4-hydroxyphenyl)acetamide, or 4′-hydroxyacetanilide); analgesics, e.g., Tylenol. 3. The methyl ester of a dipeptide. Solution: Aspartame or N-L-α-aspartyl-L-phenylalanine methyl ester; a “lowcalorie” sugar substitute, e.g., Equal, NutraSweet, used as a sweetener in many “diet” products, e.g., Diet Pepsi.
Notes W A handout for participants in this consumer-chemical hunt is available on JCE Online at http://jchemed.chem.wisc.edu/Journal/issues/1999/ Nov/abs1503.html. 1. For the purposes of this article, items have been arranged so that those numbered 1–11 are most suitable for students with no knowledge of organic chemistry. Items 12–15 could be added for students who have covered a small amount of organic chemistry. Items 16–25 require a more detailed understanding of organic chemistry. 2. The brand-name products listed are all sold in Canada, but are not necessarily available elsewhere.
Literature Cited 1. Last A. M. Chemistry in Action! 1996–1997, 50, 49–50, 58. 2. Last A. M. C3 News 1996, 21(4), 4, 7. 3. CRC Handbook of Chemistry and Physics, 76th ed.; Lide, D. R., Ed.; CRC: Boca Raton, FL, 1995.
Journal of Chemical Education • Vol. 76 No. 11 November 1999 • JChemEd.chem.wisc.edu
