Magic Bullets: Chemistry vs. Cancer

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    In a Puff of Smoke:
    Something's Burning: Combustion

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    Safety
    Materials
    Procedure Tips
    Optional Activity
    Relevant National Science Education Standards
    Relevant New Jersey State Science Education Standards

    Introduction

    There are two parts to this activity. The first part is a standard lab exercise used to demonstrate the common products of combustion—water and carbon dioxide. The second part—the optional part—should be done only if your school permits the use of real cigarettes in laboratory work. Consultation with an administrator is probably wise. You may also want to inform parents about this optional part of the activity if you choose to include it. The procedure for the optional part of the activity does not appear on the student page to allow you discretion in its use.

    Safety

    General Safety Guidelines

    The following MSDS sheet is available online from Cornell University:

      Calcium hydroxide

    Materials

    For this activity, each lab group you will need:

    1. a candle anchored to a can lid by slightly melting the bottom of the candle and fusing the candle to the lid. Warn students about possible sharpness of the lids.
    2. A 400 ml beaker or jar (250 ml beakers or smaller tend to interfere with the candle flame and result in incomplete combustion.)
    3. Gas lighter
    4. Cobalt chloride paper, 2 strips
    5. Absorbent paper towel
    6. Aluminum foil large enough to cover the mouth of the beaker or bottle
    7. 30 ml of limewater (saturated solution of calcium hydroxide, freshly prepared)
    8. soda straw
    9. test tube

    Procedure Tips

    1. Caution student about lighting candles and about their behavior around lighted candles.

    2. Be sure the beakers or bottles are completely dry after Step 6.

    3. As student pour the limewater into the beakers after the flame goes out, advise them to disturb the beaker as little as possible. Strong convection currents may tend to remove some of the carbon dioxide.

    4. The limewater may be flushed down the drain

    Optional Activity – Burning Cigarette

    A. Materials

    You will need for each team in your lab:

    1. a plastic bottle (300-500 ml works well). You may want to require that students bring these to school several days in advance so that you can drill the tops.
    2. A 5/16” drill bit is just about the right size for a cigarette
    3. Supply of clay
    4. Cigarette
    5. Water

    B. Procedure (For Students)

    1. You will need to bring to class a clear plastic bottle with top, like the ones in which bottled water are sold. Smaller bottles are better than larger ones. Write your name on the bottle and give it to your teacher the day before the experiment is assigned.

    2. Your teacher will drill a hole in the cap of the bottle just large enough for you to insert a cigarette. If the fit is not tight, seal the space around the cigarette with modeling clay. If the cigarette is a filter brand, the filter goes towards the inside of the bottle.

    3. Ask your teacher to light the cigarette.

    4. Gently squeeze the bottle and release the pressure. Alternate these steps until the entire cigarette is “smoked”.

    5. Extinguish the cigarette by placing the end under a stream of water and carefully remove the remainder of the cigarette from the bottle. Place a piece of masking tape over the hole.

    6. Allow the bottle to stand upright overnight. Observe the contents the following day.

    7. Remove the cap and smell the contents.

    8. Add about 20–25 ml of water to the bottle and swirl.

    C. Questions on Observations

    1. What did the contents of the bottle look like at the end of the burning of the cigarette?

    2. What did the contents look like the next day?

    3. Did the contents have any odor?

    4. Are the contents soluble in water?

    5. What role does the bottle play in the way people smoke cigarettes?

    Relevant National Science Education Standards

      Unifying Concepts and Processes — By examining the myriad of combustion products the students learn the complexity of a system such as combustion.

      Physical Science — Understanding of chemical reactions is central to the activity.

      Science in Personal and Social Perspectives — The students should grasp the connection between smoking and cancer.

    Relevant New Jersey State Science Education Standards

      5.1 By examining the myriad of combustion products the students learn the complexity of a system such as combustion.
      5.2 The activity involves conducting systematic observations, interpreting and analyzing data, drawing conclusions, and communicating results.
      5.8 Understanding of chemical reactions is central to the activity.

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