Chlorine Can Bring Chemistry to Life: Introduce Students to Chemistry Without Tackling the Whole Periodic Table at Once

DOCUMENT RESUME

ED 393 650 SE 056 326

AUTHOR Selnes, Marvin TITLE Chlorine Can Bring Chemistry to Life: Introduce Students to Chemistry without Tackling the Whole Periodic Table At Once. INSTITUTION Chlorine Chemistry Council, Washington, DC. PUB DATE 92 NOTE 17p. AVAILABLE FROM Chlorine Chemistry Council, Suite 300, 1901 L Street, N.W., Washington, DC 20036. PUB TYPE Guides Classroom Use Teaching Guides (For Teacher) (052) Guides Classroom Use Instructional Materials (For Learner) (051)

EDRS PRICE MF01/PC01 Plus Postage. DESCRIPTORS *Chemistry; Science Activities; Science Instruction; Science Interests; *Scientific Concepts; Secondary Education; Student Interests; Worksheets IDENTIFIERS *Chlorine

ABSTRACT Recognizing basic elements as building blocks is essential to the study of science, and looking closer at one element in particular, chlorine, can help ignite students' interest in chemistry. This document contains a 2-day study of building block chemistry using basic concepts and easy-to-find materials. Teaching materials include objectives, safety notes, disposal of solutions, teaching strategies, sample student data table, chlorine background information, chlorine chemistry and product tree, and student worksheets. (MKR)

*********************************************************************** Reproductions supplied by EDRS are the best that can be made * from the original document. * Introduce students to chemistry without 1 1.o'cience Scope Article Reprint tackling the whole periodic table atonce. I 2.

3. _

4._

7. PERMISSION TO REPRODUCE THIS U 8 DEPARTMENT Of EDUCATION 1 MATT RIAL HAS REEN G ANTE BY , '..n' ( rl.s, abnnel Freswelc end IinpowrnnI i .;A TIONAI (IF SOURCES INFORMATION CF NTF (4 IERICI 8. ',.s hal been reproduced es I.On IN. pel.0 CO ONISnittinn 9. ..4 ,/,blimp% hilrf. f.en mode ro .mprov PC.Ofil, hon r)..II.Iy 10. TO THE EDUCATIONAL RESOURCES I ol r10.,c ormons 414110in W., d u ^,ero clnol 44c0330,1r ,notflyent flU.$' INFORMATION CENTER (ERIC) 1 po.( r

TI BEST COPY AVAILABLE MARVIN SELNES Ask a class of middle-schoolers sium, magnesium, hydrogen, and to open their textbooks to carbon are true building blocks. What do tents, the periodic table and two They combine readily with other jogging shoes, lightning-fast reactions are likely to elements to form compounds. occur: eyes glaze over and brains These "building block" elements cosmetics, and change channels Why? Because at can be likened to the foundation schoolbooks have in first sight, all those chemical sym- of a building: The reactions they common? That's a bols and little blocks send one spark are the basis of countless message, "Huhhh?" chemical formations. good question to In reality, those Hocks represent Recognizing these elements as ask your science more that 100 pure elements that building blocks is essential to the combine to build just about every- study of science. And looking students. Looking thing in the world. That's a pretty closer at one element in particu- for the answer will awesome idea, even if your hero is larone of the liveliest on the lead to an eye- Bart Simpson. periodic tablecan help ignite Even more incredible is the fact students' interest in building block opening lesson in that just a handful of those ele- chemistry. building block ments make up over 99 percent of the Earth's crust, atmosphere, and chemistry. oceans by weight. Oxygen, chlo- Marvin Seines is a science supervisor for rine, silicon, aluminum, iron, phos- the Sioux FalLs School District in South phorous, calcium, sodium, potas- Dakota. Chlorine, an element Chlorine and public health munities recognize that the benefits that's everywhere Because water is so basic to our of disinfected drinking water out- Of aIt the elements, chlorine is existence, ensuring safe drinking weigh the potential risk. But why among the most active. It is almost water also would be a natural topic not find out for yourself? Explore never found free, or uncombined, for student exploration and class these issues with your students. because chlorine teams up with discussion. For example, the Latin As a class, weigh the risks and nearly every element it meetsin American cholera epidemic in the benefits of water disinfection. nature, in the research lab, or at a news over the past year is a shock- Talk with your local public manufacturing plant. ing reminder of what can happen health officials to learn more about That's why chlorine is often when drinking water is not ad- the threat of waterborne diseases found in some surprising places and equately disinfected. In fact, it is and the use of chemicals (including products. Chlorine makes up two estimated that more than 25,000 chlorine) for water disinfection. percent by weight of all sea water children worldwide die every day Contact your local water-treatment on Earth. Chlorine is in our bodies from causes related to dirty water. authorities to arrange a visit to a and in our blood; it forms the hy- At the same time, questions local water plant for a close-up drochloric acid that helps our have been raised about potential view of how water is made safe to stomachs digest food. While most risks from drinking water that has drink. Conduct library research to people are aware of chlorine's use been disinfected. While disinfec- learn morc about waterborne dis- in swimming pools, in laundry tion eradicates such life-threatening eases on a global scale. Perhaps bleach, or as a drinking water dis- diseases as cholera, typhoid, and most educational, facilitate class infectantthey may never guess dysentery, some studies suggest it discussion on what students have that chlorine is used to make tents, also may slightly increase the risk learned, including how society uses jogging shoes, telephones, cosmet- of certain types of cancer. The science to weigh risks and benefits ics, or schoolbooks. scientific and public heahh corn- in areas such as public health. Chlorine compounds are used in the production of thousands of consumer goods, pharmaceuticals, and industrial products. The pro- From whiter whites to Michael Faraday, and Humphry cess can be very complex, such as leukemia medications Davy (who first proved chlorine the use of chlorine compounds in Chlorine, the seventeenth atomic was an element) all experimented making polyester or polyvinyl chlo- element, was discovered in 1774 by with chlorine. But it wasn't until ride (PVC) products, such as vinyl the Swedish chemist Carl Wilhelm early this century that chlorine's rain gear and house siding. Or it Scheele. His find heralded the way public health and commercial ben- can he extremely simple. Combin- for whiter whites. The bleaching efits became _vident. Chlorine was ing sodium with chlorine yields properties of this new gas were an found to be an effective drinking sodium chloride, a product that's instant improvement over the only water disinfectant, virtually elimi- part of many mealstable salt. other method of lightening fabrics: nating the threat of waterborne Without chlorine compounds, bleaching them in the Sun for six disease. About the same time, the we wouldn't have many of the weeks. However, there was one discovery of an economical way to products and services that we often drawback. Chlorine gas rusted the cool and pressurize chlorine gas take for granted. Skeptics need metal machinery and equipment of paved the way for widespread corn- only look around the classroom the day, so it was not widely used. meic ial applications. notebook paper, electronic gadgets, But in 1789, chlorine was com- Today, chlorine is produced by pencil erasers, cassette tapesto bined with a potash solution that electrolysis. An electrical current grasp the real-life impact of chlo- made it easier to use. passed through salt water (from the rine and other building block Interest in chlorine grew rapidly. sea or underground salt deposits) chemicals. Antoine Lavoisier, james Watt, splits p)sitive m)dium and negative

JANUARY1 9 9 3 chloride ions. Since opposite compounds and the activities on Lesson objectives, teaching strate- charges attract, the negative chlo- the attached poster can help you gies, and key discussion points are rine ions collect at the positive deliver a two-day lesson on provided. Student hand-outs can poles to form molecular chlorine "What's in this stuff?" easily be photocopied from the gas. The gas is dried, chilled, and Start by awing your students back of the poster. The materials pressurized or converted to liquid with magic: Turn "wine" (water used in the experiments can be for storage and shipping. Chlorine tinted with red food coloring) into obtained inexpensively through any is used as a building block in a water right before their eyes. school science supplies vendor. range of products from laundry Household bleach, or sodium hy- Always follow your schools' safery bleach to ski boots to leukemia pochlorite, is the secret ingredient precautions regarding chemical use, medications. that clears up the water. Once the including providing protective secret is out, point to the poster to eyewear for students. launch a hunt for all the unex- pected things chlorine compounds More building block chemistry Tune in students' help build. On day two, give stu- For your free copy of the Building imaginations to dents an opportunity to put chlo- Blocks of Our World: Chlorine video building block rine to the test themselvesexperi- or additional activities that illus- menting with a variety of chlorine trate the use of chemicals in every- chemistry and hear saltsto see what happens when day life, please contact Schools, some natural chlorine combines with other com- Chlorine Chemistry Council pounds. For instance, when light 2501 M Street, N.W. reactionsthe blue chunks of copper chloride Washington, D.C. 20037 "ahhs" and "ohhs" react with ammonia, they turn dark (202) 887-5418 of discovery. blue. However, copper chloride's reaction with water and aluminum Other activity resources is surprisingly different; the new Chemical Education for Public Introducing building mixture bubbles, gets warm, and Understanding Program (CEPUP) block chemistry turns brown. A video that comple- Lawrence Hall of Science Chlorine and chlorine compounds ments the lesson plan is also avail- University of California are a good way to introduce your able free from the Chlorine Insti- Berkeley, CA 94720 students to building block chemis- tute. (See box for information). (510) 642-8718 try without tackling the whole The accompanying poster and The American Chemical Society activities were developed and periodic table at once. Education Division On its own, chlorine has a dis- tested by science teachers, with 1155 Sixteenth Street, N.W. tinct odor, although smelling chlo- support from the Chlorine Insti- Washington, DC 20036 rine is not recommended. Liquid tute, to supplement regular class- chlorine is amber in color. And in room chemistry studies. The objec- In addition, the Chemical Manu- low concentrations, chlorine gas is tive of the lesson plan is to help facturers Association publishes an nearly invisible. But when chlorine students understand that chlorine is education resource guide that iden- combines with other elements it just one of several important single tifies classroom support material does things that will keep students elements or building blocks essen- available from more than 50 tuned in. Chlorine compounds can tial to the production of a variety chemical companies. turn blue, brown, or sparkling of different compounds. The Chemical Manufacturers white. They can change odor or The lesson procedures and guide- Association have none at all. They can be hot lines are complete, easy-to-use Education Services or cold. They can bubble, liquefy, resources and tools for teachers. 2501 M Street, N.W. or harden. The ever-changing They can be implemented as they Washington, DC 20037 physical properties of chlorine are or adapted to meet yourneeds. Alm

Introduce your students to chemistry without tadding the whole periodic table at once.

Recognizing basic elements as building blocks is essential to the study of science. And looking closer at one element in particularChlOrinecan help ignite students' interest in chemistry. The following two-day study of building block chemistry uses basic concepts and easy- to-find materials. Additional free materials that can extend your lesson- on chemicals in everyday life are available by writing to: Schools, Chlorine Chemistry Council, 2501 M Street, NW, Washington, DC 20037.

Chlorine: Disposal of solutions One very special building block These solutions can be disposed of in the sink or collected for later disposal, according to existing local Objectives regulations. Always check for local restrictions on The students will: disposal. rtl Understand that chlorine is one of several impor- Teaching strategies tant single elements or "building blocks" Day OneBuikling Awareness of matter which can be combined to produce a (Before class, fill two clear plastic 8-ounce cups half variety of different compounds. full of warm water. Add one drop of red food coloring Observe and record different chemical and to one cup. Add 3 4 droppers full of full strength physical properties of selected chlorine compounds household bleach to the other. If larger containers are Understand that chlorine compounds are used to used, adjust the proportions accordingly.) make products that play important roles in homes, Ask students to observe very closely, because you are schools, and industry. about to perform some chemical "magic." Display the Safety notes two cups. Ask the students to describe what they see. Instruct students not to bring the chemicals into Most will say that one is a solution of red food coloring contact with their eyes, skin, nose or mouth. Re- and the other contains water. Pout the red solution into mind students to wash their hands after the activity. the "water" and set aside. In 30 - 60 seconds (exact Follow your school policy regarding the use of time varies) the solution will mysteriously clear! student safety eyewear. Safety eyewear is Continued on back. strongly recommended. la+

Chlorine Chemistry Council, 2501 M Street, N.W., Washington, D.C. 20037 Continued

Ask students to explain what Day TwoThe Science assisting as needed. Be sure that stu- they have observed. Explain, if Recall the list of chlorine ,:ompounds dents follow recommended safety needed, that the second cup the students took home yesterday. precautions when using these materials. contained bleach, or sodium Discuss their findings. Review the The chloride salts can be obtained easily hypochlorite. (You may wish to "building block" concept with the and inexpensively from almost any contrast observation and inference students, noting that chlorine combines vendor of school science supplies, or at this time.) Tell students that with many other elements to form contact local high school chemistry chlorine is present in many other different compounds. each with differ- teachers. Litmus or other indicators can compounds that are a common partent chemical and physical properties. be used instead of pH paper. Sample of our daily lives. Distribute Tell them they will get a chance to student data tables and answers are student sheet 1, "Chlorine in our work with several different chlorine listed below. lives," and ask students to mark offcompounds. Distribute student sheet 2, Discuss student results and summarize those items they use or see in "Exploring chlorine compounds." the main points of the activity. If school. Discuss the procedure with students. students had trouble observing the Discuss their responses. Explain Highlight the difference between temperature change with calcium that chlorine likes to combine with physical properties (appearance, color, chloride, tell them to try again with other elements and compounds, odor, etc.) and chemical properties, more solid. Hydrogen gas is given off and scientists have found ways for which are determined by the interaction when copper chloride reacts with chlorine to help build or improve of the chlorine compound with other aluminum foil. Iron chloride reacts with things. Define "element" and substances. aluminum foil, but much more slowly, "compound" as needed. Ask them Make materials available and allow taking several minutes to produce to take the student sheet 1 home to students to complete the activity, observable results. check for household items containing chlorine or requiring chlorine . during the manufacturing process.

Tell them they may want to ask temperature acid, base aluminum foil color change their parents for help. compound appearance change in wateror neutral reaction with ammonia Introduce chlorine as an impor- yeaow-brown bubbles, gets red-brown Fr-onchloride no change aci d warm, brown solid solid forms tant "building block," one of a chunks large white calcium chloride neutral no reaction no change handful of single elements that irregular chunks gets warmer combine to form most of the matter on the carth. Write the names of sodium chloride white crystals no change neutral no reaction no change the following elements on the light blue bubbles. gets dark blue cupric chloride no change slightly acid chalkboard or overhead projector: chunks warm, brown solid solid forms oxygen (0), silicon (Si), aluminum Answers to questions 2. How do you explain the differences in the (Al), iron (Fe), calcium (Ca), 1. Which of the chlorides seem to have the chemical and physical properties of these sodium (Na), potassium (K), most similar physical properties and chemical chlorides? Student answers should indicate that magnesium (Mg), hydrogen (H), properties? Sodium and calcium chloride seem all the compounds contain chlorine. Therefore to have the most similar properties. Although any differences in properties must be due to the phosphorus (P), chlorine (0), and other chemicals present in the compounds. carbon (C). Use chemical abbre- dissimilar in appearance and in their reaction with water, they are both white, form neutral 3. How do the observations you made in this viations if desired. Tell students solutions and do not react with aluminum foil activity support the idea of chemicals as "building that these elements are sometimes or ammonia. Cupric and iron chloride both blocks?" (Note that chlorine is a gas at room called "building blocks" because form acid solutions in water and react with temperatum and has a strong odor.) Each chloride they make up over 99% of the ammonia and aluminum foil. The least similar is a solid at room temperature and has no detectable earth's crust, atmosphere, and physical properties and chemical properties? odor. Each chloride has chemical and physical Answers vary. Cupric chloride has no common oceans, by weight. properties that differ from chlorine gaEand each properties with either ammonium chloride or other chloride. These changes msult from the Tell the students that tomorrow calcium chloride. Others may have some different elements or "building blocks" that they will explore a variety of common properties. combine with chlorine to form each compound. chlorine compounds. Chlorine: A Common Building Block Chlonne, oxygen, silicon, aluminum, iron, cal- like hospitals, households and swimming pools use cium, sodium, potassium, magnesium, hydrogen, chlorine-based compounds (such as bleach) for their phosphorous and carbon make up over 99 percent ofdisinfection needs. About 85 percent of the top- the earth's crust, atmosphere and oceans (by weight).selling medicines are manufactured using chlorine These elements are truly "building blocks"they chemistry. Chlorine also is used to manufacture combine with other elements to form our world. versatile plastics such as vinyl (polyvinyl chloride). Crop-protection chemicals based on chlorine help feed the world and ward off insect-borne diseases. Chlorine chemistry Chlorine helps ensure that products like disposable Chlorine is commonly found in nature, but almost diapers and paper towels are strong and absorbent. always in combination with other building blocks. Chlorine also plays a role in the classroom. For Chlorine's structure makes it very reactive (its outer example, it is used to make the vinyl and polyester shell is missing just one electron), which makes it in backpacks, is a critical component of computer attractive to other atoms and molecules. Because it chips, helps in the production of rubber for pencil is so reactive, it is very useful to chemists, engineers erasers, and strengthens and brightens notebook paper. and other people involved in making things we use every day. When combined with other chemical building blocks, chlorine can change the nature of a Are all chlorinated compounds alike? substance, and build or improve a product. Just because a chlorine molecule is attached to To be used in manufacturing, chlorine must first besomething does not make it the same as something separated from the other elements with which it is else containing chlorine. For example, consider the combined. Manufacturers use a process known as following four salts. All contain chlorine, but they "electrolysis," which breaks down salt water into are not alike; each contains a different setof building basic components, including chlorine. An electrical blocks and offers unique characteristics. current passes through the salt water and splits apart the positive sodium and negative chloride ions. Iron (ferric) chloride (FeCI3): Used to make Since opposite charges attract, the negative chloride pigments, inks and dyes, in controlling odors and ions collect at the positive poles and form molecular removing phosphates from municipal waste water, in chorine gas. The gas is dried, chilled and pressur- photographic processes, and as medicine. ized, or converted to liquid for storage and shipping. In other words: Calcium chloride (CaC12): Used (when in a water Salt+Water electricitYChlorine+Caustic Soda+Hydrogen solution) as antifreezes and in refrigerating solutions, in preservation of wood and stone, in the manufac- or: ture of glues, cements and fireproof fabrics, and to 2NaCL + 2H20 electricity Cl2+ 2NaOH +1-1: speed the setting of concrete.

Using chlorine Sodium chloride (NaCI): Used in ceramic glazes, Where does chlorine go then? Into thousands ofsoap manufacturing, fire extinguishingsolutions, things you see and use every day. Every time you andof courseas table salt. drink a glass of water, read a newspaper, put on a vinyl raincoat, brush your teeth or drive a car, you Cupric chloride (CuC12): Used in wood preserva- are using chlorine in some form. tion, in the fabric dyeing process, and, when mixed Chlorine guards against diseases such as cholera, with other copper salts, as an agricultural fungicide. typhoid fever and dysentery in drinking water. Places

Chlorine Chemistry Council, 2501 MStreet,N.W.,Washington, D.C. 20037 Chlorine in our lives Many of you may know that chlorine is used in swimming pools, and to keep our watersafe to drink. But chlorine has many other important uses as well. It is a "buildine block" in thousandsof products: medicines, plastics, other chemicals, paper products, etc. Chlorine is used to manufacture each of the following products. Which have you usedrecently? Circle the products you have used or seen used at school in the past week. Take this sheet home. Checkthe products you have used at home in the past week. Ask your parents, or an adult at home, to look over your answers.Add items to the list if you can.

tents awnings luggage seat covers

golf bags bicycle seats nylon floor coverings

wallpaper camera film insulation baby strollers

air conditioners car bumpers fabric dye perfume

deodorants drain cleaners household bleach toothpastes

paint removers dry cleaning adhesives cosmetics

sleeping bags electronic parts shoes toys

adhesive bandages erasers oil additives fungicides

soft drink bottles fire extinguishers PVC pipe detergents

fire resistant fabrics fishing poles & line handbags & purses prescription drugs

gelatin flash bulbs fireworks hair permanents

i toothbrushes furniture fabrics pen tips soft drinks

automobile tires garden hose newspaper guitar strings

baby cribs compact discs boats shower stalls

spot removers leather processing circuit boards dental cements

coffee filters notebook paper paper towels seat cushions

, paint plastic bottles household glue anesthetic

refrigerators upholstery exercise equipment polyester fabric

umbrellas seat covers window screens telephones

gasoline semiconductors mirrors food additives

brushes camera cases photographs vitamins

jogging shoes tennis shoes boat sails ant, ireeze

tennis racket strings caulks and sealants card tables & chairs paper & plastic bags

watch straps wallets raincoats audiotape

sunscreens weed killers computer parts power tool parts Exploring chlorine compounds

Purpose Procedure You will observe and compare the physical and chemical properties of different chlorine compounds. 1.Examine each of the chlorides with the magnifying glass. Record your results on the data table. Materials 2. Place half a small spoonful of iron chloride in a test tube or Magnifying glass chem plate. Add 20 drops of water. Feel the outside of the Aluminum foil, 1 x 4 cm strip tube. Record any up or down temperature change in the data pH paper, 4 strips table. Repeat for the other chlorides. Chemplate or 4 small jars or test tubes (with rack) Small jar of tap water 3. Dip a piece of pH paper in the iron chloride solution. Record the acid/base properties in the data table (red or pink = Dropper bottle of household ammonia acid, no change = neutral, light green or blue = base). Repeat Dropper for the other chlorides. Small spoon Paper towel 4. Tear the aluminum foil into four equal pieces. Add one of the pieces to the iron chloride solution. Record your observa- Small spoonful each of: tions on the data table. Repeat for the other chlorides. Clean iron chloride and dry the test tubes or chem plates. calcium chloride sodium chloride 5. Place half a small spoonful of iron chloride in a clean test cupric chloride tube. Add 20 drops of water. Add five drops of household ammonia. Record your observations in the data table. Repeat Safety for the other chlorides. Please be sure to use safety eyewear and to follow all other safety precautions. Do not taste or smell any of Follow your teacher's instructions for clean-up and return of the chemicals. materials.

Data table

compound appearance temperature acid, base or aluminum color change change in water neutral foil reaction with ammonia

iron chloride

calcium chloride

sodium chloride

cupric chloride

Questions (answer on back) 1.Which of the chlorides seem to have the most 3.How d 3 the observations you made similar physical properties and chemical properties? in this activity support the idea of The least similar physical and chemical properties? chemicals as "building blocks?" 2. How do you explain the differences in the chemical and physical properties of these chlorides? Eliminating Microorganisms from Water

Adding chlorine to drinking water has virtually Procedure eliminated waterbome diseases such as cholera in 1. Boil about one quart of water (tap or freshwater) for two North America by destroying disease-causing microor- minutes, let cool to room temperature, and pour into a thor- ganisms. You can safely and easily demonstrate how oughly clean, wide-mouth glass vessel. Put a handful of dry chlorine protects public health by removing micro- hay, straw or grass into the vessel and set it aside in a darkened scopic life from a water culture that you create. place at room temperature for seven to nine days. You are creating a water culture that will teem with microscopic life.

Materials 2. After the wait, place a glass slide on the microscope and use Tap or fresh water (untreated water will yield the eyedropper to put a drop of the water culture on the slide. more microorganisms) (Place a cover slip on the water culture drop). You and your Wide-mouth glass vessel that holds about a quart students will be able to view many microscopic life forms. of water (e.g., Mason jar) and several smaller including protozoa (amoebas, parameciums) and nematodes glass vessels (microscopic worms) moving around. These are the same Container and heat source to boil water types of organisms which live in surface waters and are removed during the water-chlorination process. In fact, certain Handful of dry hay or straw (dry, untreated grass protozoa are responsible for amoebic dysentery and giardia. will do) which are common illnesses associated with water that is not Microscope (minimum 100 power) with glass slides properly chlorinated. Use several slides to sample water and Liquid laundry bleach (5.25% sodium hypochlorite) view life forms from different parts of the culture. Measuring cup 3. Now pour about one cup (eight ounces) of the water culture Eyedropper (being careful not to spill) into another clean container. Make Plastic st;rrer up a solution of one part bleach to nine parts water in another Thin rubber gloves container. After stirring the solution and rinsing the eyedropper, place about 20 drops of bleach solution into the Safety goggles or glasses cup of water culture; stir the water culture/bleach solution and Paper towels let sit for about one minute. Thoroughly rinse the eyedropper in tap water and examine several drops of the bleach-treated culture. You should see no animals still alive in the water. Safzty Wear rubber gloves during the experiment. Do not allow culture to contact your body (people with cuts Suggestion should not touch the culture). Arrange a field trip for your class to the local water treatment Follow all label directions on bleach (it will bleach facility to learn where tap water comes from and why water clothing). disinfection and source water protection are important. Dis- cuss tradeoffs involved (e.g., disinfection by-products vs. Keep hands away from face during the experiment. microbial contamination). Wear safety goggles/glasses when handling the bleach. Thoroughly clean all equipment, gloves and hands instructor's notes when fmished. If microscopes are not available, use pond water and add Dispose of the cultur c. in the toilet. Dispose of chemical fertilizer and set in direct sunlight, allowing bleach solution in sink followed by a five-minute flush eutrophication to take place. with cold water, and dispose of other materials in a clean trash bag.

Chlorine Chemistry Council, 2501 M Street, N.W., Washington, D.C. 20031 Balanced Equations for the Chloride Salt Activity

ammonium chloride + ammonia NH4C1 (aq) +NH3 (aq) --> no reaction

ammonium chloride + aluminum foil NH4C1 (aq) + Al (s) --> no reaction

cupric chloride + ammonia CuC12 (aq) + NH3 (aq) --> Cu(NH3)C12 (aq) [note: some Cu(OH)2 may be produced]

cupric chloride + aluminum foil 3CuC12 (aq) + 2A1 (s) --> 3 Cu (s) + 2 AlC13

ferric chloride + ammonia FeC13 (aq) + 3 NH3 (aq) + 3 H20 --> Fe(OH)3 (s) + 3 NH4C1 (aq)

ferric chloride + aluminum foil FeC13 (aq) + Al(s) --> A1C13 + Fe (s)

calcium chloride + ammonia CaC12 (aq) + 2 NH3 (aq) + 2H20 --> Ca (OH)2 + 2 NH4C1 (aq)

Chlorine Chemistry Council, 2501 M Street, N.W., Washington, D.C. 20037 Natural Chlorine? You Bet! By Dr. Gordon W. Gribble Chlorine's Natural Abundance Most people know that table salt a natural organohalogens. A species of marine worm from the mineral essential for the proper functioning of our Gulf of Mexico secretes 20 different halogenated nervous and muscular systems is sodium chloride. compounds, mainly phenols. But many would be surprised to know that hundreds, probably thousands, of organic chlorine chemicals are produced by an array of biological and natural chemi- Chlorine Compounds Are Crucial for Survival cal processes in our environment. Many of these Extensive research has shown that these chemicals are identical to highly publicized man- organochlorine compounds are not derived from made organochlorines: chlorophenols, chlorinated pollutants but, rather, are produced by individual hydrocarbons, PCBs, CFCs and dioxins. But many organisms for very specific purposes. They play an others are entirely new molecular entities, many of essential role in the organisms' survival, and their which possess extraordinary and important bioloRical ability to synthesize these compounds has evolved properties similar to those of penicillin, morphine and over time under the stress of natural selection. the new anti-cancer drug taxol. Many of these natural organochlorine compounds As a fundamental chemical element, chlorine is not are used in chemical defense as feeding deterrents, only abundant in the Earth's crust (ranking 18th in the initants, or pesticides or to facilitate food gathering. list of elements) but it is also ubiquitous in our soil, One marine algae compound, called telfairine, which is rivers, lakes, trees, plants and, of course, oceans. Like chemically similar to many chlorinated pesticides, is 100 other common elements carbon, hydrogen, oxy- percent lethal to mosquito larvae at ten pans per million gen, nitrogen, sulfur, phosphorous that are present (ppm), and a related natural chlorinated chemical is three in all living things, it would appear that chlorine and times more effective than the commercial chlorinated the other halogens (bromine, iodine and, to a lesser pesticide Lindane against mosquito larvae. extent, fluorine) are present as well. Although only 30 natural organochlorines had been discovered by Other organochlorines serve as hormones. Plants such 1968, as of April 1994, this number has grown to over as lentil and sweet pea use 4-chloroindoleacetic acid as a 1000. And more are being discovered every month. growth hormone, and a Chinese folk medicine plant contains five natural chlorinated compounds. The Organochlorine and the related organobromine German cockroach manufactures two chlorinated compounds are produced naturally by marine crea- steroids as trail pheremones used in food gathering; the tures (sponges, ccrals, sea slugs, tunicates, sea fans Lone Star tick produces 2,6-dichlorophenol as a sex and jelly fish) and seaweed, plants, seeds, trees, fungi, pheremone; and locusts employ chlorinated proteins to lichen, algae, bacteria, microbes and insects. The strengthen the cuticle. A Penicillium species produces ocean is the single greatest source of different orga- 2,4-dichlorophenol, the same chemical that man uses to nochlorines. Nearly 100 different organochlorine. synthesize the herbicide 2,4-D. Recently, a tiny organobromine and organoiodine compounds are Ecuadoran frog was found to secrete a chlorinated present in "limu kohu," the favorite edible seaweed of alkaloid, which is 500 times more powerful than mor- most Hawaiians. Other seaweeds produce phine as a pain-killer and which is believed to thwart bromoform, chloroform, carbon tetrachloride. methyl predators such as birds. bromide and numerous polyhalomethanes. It had been reported that ozone destruction in the lower It is only a matter of time before many natural Arctic atmosphere is linked to the bromoform that is organochlorine compounds are found in humans. produced in large quantities by sea ice algae. As a Indeed, organoiodines (thyroid hormones) and one matter of fact, the "smell of the oceans" is probably organobromine compound are well known to be due to these volatile organochlorines and other present in humans. Continued on back. 1 -8. 42 Chlorine Chemistry Council, 2501 M Street, N.W., Washington, D.C. 20037 Continued

An astonishing research development is the discovery This natural chemical process occurs in forest fires that our immune system actually uses chlorine, and volcanos_ In fact, it has been estimated that the bromine and iodine to halogenate and kill invading largest [natural] source of dioxins in the environment microorganisms. For example, cellular enzymes in is from forest fires, of which 200,000 occur annually mammalian white blood cells oxidize natural blood (most of which are caused by lightening; e.g., the chloride (bromide and iodide) into active chlorine. Yellowstone fires in 1988). Indeed, dioxins have been This causes the death of pathogens (bacteria, yeast, identified in 100-year-old preserved soil samples. fungi and even tumor cells) by chlorination. Chlorina- tion is apparently as natural a biological process as Both Mount St. Helens and Hawaii's Kilauea, the blood clotting or salivation. latter of which has been erupting since 1983, produce methyl chloride. The Kamchatka volcanos in Siberia and Guatemala's Santiaguito volcano emit CFCs in Part of Nature's Recycling Process quantities well above background levels. Many Nature is an incredible recycling center. Insects, organochlorines now known to be produced by microorganisms and fungi all break down dead matter volcanos including tetrachloroethylene, chloroform, to simpler chemicals for reuse. One such organism, carbon tetrachloride, methylene chloride and several the white-rot fungus, decomposes dead trees and other of the CFCs, were formerly thought only to result forest plant material. A major natural byproduct of from the actions of man! From one Kamchatka this biological decay is methyl chloride volcanic vent, CF2Cl2 was detected in levels of 160 (chlommethane) the simplest organochlorine. Five ppb, 400 times that of the background atmosphere. million tons of this chemical are produced naturally Such natural chlorine and fluorine compounds are every year. This amount dwarfs the 26 thousand tons produced by the combustion of organic material, such produced annually by man. Some scientists believe as vegetation, sediments or fossil soils in the presence that this natural methyl chloride is an innate regulator of chloride and fluoride minerals. The extent to which of stratospheric ozone. these natural organochlorines and CFCs contribute to the global picture vis-à-vis ozone depletion remains to Another breakdown process involves the biodegra- be seen. A study of Mount St. Helens ash revealed dation of humic and fulvic acids into phenols and the presence of three previously unknown isomers of chlorophenols. Several studies have shown that polychlorobiphenyls (PCBs) presumably formed this natural production of chlorinated phenols from the combustion of carbon- and chloride-rich outweighs man-made sources. For example, the plant material during the 1980 eruption. total pool of chlorinated compounds in peat bogs in Sweden is several hundred thousand tons in areas where these chemicals can only be of natural origin. By comparison, the largest industrial source of these chemicals in Sweden is from the paper pulp industry, which produces 10,000 tons per year. Although "environmentalists" try to link the presence of organochlorine compounds in water samples to man-made causes, naturally produced chemicals have been found in ground- water samples dating back 5200 years.

Because organic matter contains naturri chloride (up to 10,000 ppm) and this reacts to form organochlorines at high temperatures, methyl chloride, Excerpted with permission from Priorities, a methyl bromide and many other haloalkanes are publication of the American Council on Science produced when organic matter bums. and Health. Washington, D.C. (Vol. 6, No. 2, 1994). CHLORINE CHEMISTRY AND PRODUCT TREE - Luggago handbags, and umbrellas Sugar refining Vinyl chlonde Off [Polyinnyl chlonde Pipe and fithngs for sewer service Watch streps and brIlfolds Corn syrup Shoes and belts ood processing Gelatin Vinyhdene chlonde Polywnyfidene chlonde Packaging for food products especially meats and poultry Textile fabric coatings and paper coating Monosodium glutamate Mulhwall bags Raincoats, rainsuits. and Parkas Desullunzation agent for petroleum Brewing Iftchloroethyl ether 11,az lubtmation oils 111110.- ['last. (clear plastic bottles) Seat covers and upholstery Magnetic recording taCte Precinct. ot abyt Mendes Electronic silicone Vinyl ether Anesthetic Fibers and bristles Golf bags and recreatconal equipment lora Paints, varnishes Latex coatings Exercise equipment pad coverings Oil well acidong Catalysts and lacquers Inflatable boats and water floats Baby strollers. bibs, cnb bumper pads and Hydrochloric acid OP. Photoflash buff s Refractories HIPP- Chlorositanes emiconductors nialtress covers Production of metallic chlorides Card tables and chairs Alloys Pickling in steel manufacture Pyrotechnics Methyl chionde IP.Methylcellulose [Th ckerang agent for foods and nonfoods Woody,io vinyl coating for stereo cabinets radio Medical devices. surgical membranes and TV cabinets. TV carts, bookshelves table Rubber accelerator Polishes waxes tops, and counters Water treatment Plastics stabilizer Encapsulahon of electronic parts Cases for cosmetcs cameras binoculars hunting Opt. Silicones OP. Water repellent coatings Mies, musical instruments Production of hydrochlondes Rocket prePellants Pharmaceuticals Venous home use caulking and Containers for food products cosmetics toiletries . sealing compounds and household chemicals atex coagulating agent Polymers ton exchange resins Cosmetics and pharmaceuticals pharmaceuticals SwIrnming pool liners and covers Water treatment Garden hoses and lawn furniture Permanent wzve solutions hair care products Methyl chloroacetate Crop protection chemicals Ethyl chloride NW.Ethylcellulose NW- Inks School and office supplies such as ring binder OP- Coatings covers penal cases. book totes Chloreacetic acid Synthetic caffeine vitamin Vinyl stabilizer raper chemicals Floor coverings and decorative molding stnps Pharmaceuticals Ethylene dichloride pi. Ethylene Diarnine Softeners Wallpaper Trichloroacetaldehyde Additives for oil detergents Siding gutters and gutter leaf guards Pharmaceuticals Thickners food additives Tetrachlorophthalic Methylene chloride Window and door frames anhydride plp. Flame retardants Chloroform. Pipe and fitting, domestic corm ercial industrial [able insulation Carbon tetrachloride Topical anesthetic Film and sheeting Chlorinated olefins Fhghway stripe paint Photographic chemicals dyes and dwintecting Nonstick cookware Solar reflectrve film --Noe High-pressure lubriCants Intermediates Water treatment --Ow- agent for municipal for aluminum cans Plastic processing Electrical insulation for ',me and cable and paraffins Flame retardants Rubber antioxidants water supplies Surface coatings on autos. Photographic chemicals Adhesive and bonding agent base for synthetic tud Plasticizers for polyvinyl chlonde Punfying sugar paces Water and sewage appliance, equipment Pharmaceuticals cosmetics Automobile wnyl tops. upholstery floor mafft Sulphur dichlonde Sulphur monochlonde Detergents Bandaffls treatment P C boards composnes Paint removers process solvents Seat covenngs Erasers Epoxy resins--11111.- Household glue for metals. Dry cleaning Electrical and decorahve vinyl tapes Thionyt chlonde glass, and ceramics Adhesnes Sulfuryl chloride Oil additives Pacemaker batteries Ally! MM. Epichloronydhe Polymers - water adheshes Corroston resistant plastms Gasoline additives. hydraulic fluids Phosphorus tnchlonde Intermediates Crop protection chemicals atIonde treatment. wet Refngerants strength resins Aerosols Phosphorus pentachlonde Semiconductor manufacture CHLORINE Phosphorus oxychlonde Fire-retarding agents Photography etching and engrawng Water treatment Glycenne [Pharmaceuticals Newspaper. copy P.P.,. Crop protection chemicals Motstunpng compounds venting paper Ferric chfonde /111. PP oh an .II-r neda ut lice' yl s Paper and Coffee filters pulp Tissue Stannous chlonde Soldenng fluxes Rashes Paper towels ---1111{SSIaNbeinknzegrrnfo'r Pe'rfumesoar., I Deodorant preparations Pharmaceuticals Computer paper Zinc chlonde Dental cements and dentifrices Benzoyl chlende Perfume bases Pnnting paper (books magazines. Other metal chlorides ___10,-Eatalysts Chlorotoluenes chlorophenol Sunscreen reports, calendars etc I Benzotrichlonde Dyes Sandizers Mr swimming pools Parachlorobenzotrifitionde Indiators and stabilizers for plastics [Pharmaceuticals Household and commercial bleaches Bleaching pulp paper and textiles Dichlorobenzene Crop protection chemicals Oil resistant auto components Crop protection chemicals Chlonnated isocyanurates Water purification Cosmetics Carpet backing and seat cushions Intennerhates Detements for automatic dishivashers Pharmaceuticais Food bleaches lehre coating and eiectricai Scouring powders components Sodium hypochlonte ib. Household bleach Chloroprene --1111. Neoprene NW Shoe soles Bullet proof "glass' ."-- Disinfectant for swimming pools omputer components Windows on buses, trains, subways. Power tool housings aircraft. buildings Dtchlorophenyl 11/1. Polysullone Appliance housings Household appliance housings Paper de-Inker Algaecide bactericide Transformer thad sulf one Electronic pads ION Polyearbonales Compact discs Rpe and sheets Protective helmets and face shields Calcum hypochlonte Circuit boards Shoe uppers and hcels Containers DPotabolerawntater purification Drain cleaners Disinfectant for swimming pools TexIde manufactute Phosgene Auto bumpers and lenders Automotrve components and elecIncal Insulation Leather finishing Pigments Brush bristles and spandex fibers 1.1.1 Tnchloroethane Propylene paw Propylene oxide OW- Polyurethane 011. Adhestves Perchloroethylene Dyes Refrigerants chlorohydrin Sealants and caulking agents Piasfics Methylene chloride Propylene glycols Paints, varnishes and coatings Solvents Tnchloroethylene Spot remover Foam cushions. mattresses Coatings. paint Crop protection chetrimals Hydroxypropylacrylate [Coatings FpolaododrcialerUsves Solvents Adhesives FLubncants Anhfreeze and coolants (Degreaser Polypropylene glycols Metal working fluids Paints Flavonng extracts Dry cleaning I_Rubber Solvents Adhesives Soft-dtink syrups Plastics Cleaners Coatings Ls/bens)creams suntan lotions Electrical components Intel-mediates Conosson inhibitors Brake flulds Semi conductors Propylene glycol ethers pg.Brake fluids Cosmetics/personal care products Pharmaceuticals Titanium dioxide Corrostonxesistant Paint Mnung chemicals Crop protection chemicals CrOp protection chemicals Synthefic gemstones Isopropanolamsnes Neutralieing agent, Natural gas treatment Catalyst Plastics Paint pigment opacifiers Surfactant, Titanium metal SOURCE Charles River Associates. 1993 BEST COPY AVAILABLE / 7