Educational Innovations, $5.95 Part #GAS-150;
Microscale Gas Chemistry
Experiments with Carbon Monoxide

Link to CO data page including physical properties.

General Safety Precautions.
    Always wear safety glasses.  Gases in syringes may be under pressure and could spray liquid chemicals.  Follow the instructions and only use the quantities suggested.

Toxicity.
    Carbon monoxide has a relatively high toxicity.  The molecule binds to hemoglobin about 300 times better than oxygen, thus disabling the ability of hemoglobin to carry oxygen to tissues.  Symptoms of carbon monoxide poisoning include headache, mental dullness, weakness, nausea and vomiting.  If any of these symptoms are noted, seek fresh air.  Recovery from mild levels is rapid and complete with no cumulative effects.  Higher levels of exposure can lead to unconsciousness and death.

Chemical Caution: Sulfuric Acid
    Concentrated sulfuric acid is an exceptionally dangerous chemical.  The acid causes severe chemical burns upon contact.  If contact with the acid is suspected, wash area with plenty of water.  Contact with the eyes may cause permanent damage and possible blindness.  Wash the eyes with plenty of water and seek immediate medical attention.

Suitability.
    All of these experiments are suited for use as classroom demonstrations.  The techniques described herein are more advanced than those used in the first ten parts of this series.  Individuals attempting these experiments should be experienced with the simpler syringe/gas techniques.  These experiments are not generally advised for use as laboratory experiments conducted by typical high school students.  Advanced students or students with special laboratory skills could be allowed to generate CO(g) by this method under close supervision by the instructor.

Syringe Lubrication.
    We recommend lubricating the black rubber diaphragm of the plunger with silicone spray (available from hardware stores) or medium-grade silicone oil (Fisher Catalog Number S159-500; $34/500 mL.)

Equipment. (This equipment can be ordered from a variety of vendors including Educational Innovations, Flinn Scientific (US sales only), Micro Mole, and Fisher Scientific.  Part numbers and links to their websites are provided.)


Chemicals.

  • 8 drops concentrated sulfuric acid
  • 8 drops (0.23 g; 5 mmol) formic

  •  
        Carbon monoxide is produced by the Thermal Method.  Theoretically, this mixture will produce over 100-mL CO(g) that is >95% pure.  The production of CO is relatively fast and it typically takes 15 seconds to fill a syringe.  Upon heating this mixture, CO(g) is produced according to the reaction:

    H2SO4(l) + HCOOH(l)   CO(g) + H2SO4.H2O(l)

    This method utilizes two clean, dry 60-mL syringes connected by latex tubing to a 120 x 15 mm test tube fitted with a suitable (#0) two-hole stopper.  Short lengths of glass tubing are inserted through the rubber stopper.  (CAUTION!  Soak the rubber stopper in alcohol and lubricate the glass tubing with alcohol before inserting the tubing through the stopper.  Hold glass tubing with a thick towel while inserting!  Avoid puncture wounds!  Do not force the glass!)  Syringe plungers should move easily in barrels.  This can be facilitated by applying a thin film of silicone oil to the plunger's rubber seal.  The assembled apparatus is shown in Figure 1.  Also needed is a small flame source such as a long-nosed butane lighter or an alcohol lamp.  The left syringe, labeled 'CO' is used to collect relatively pure CO(g) and the syringe labeled 'Waste' is used to collect impure samples of gas and unwanted air.  A pinch clamp or hemostat is used to pinch closed one of the latex tubes.

        Place 8 drops of each concentrated sulfuric acid and formic acid in the test tube.  The reaction will immediately commence forming small bubbles of CO(g).  Insert the stopper firmly in order to form an air-tight seal.  Hold the heat source with one hand while manipulating the tubing clamp or hemostat with the other.  The 3-step maneuver is shown in Figure 2.

    Figure 1.

    Method for generating CO(g).  Notice that a simple long-nosed butane lighter is all that is needed to produce CO within seconds. 

    Figure 2.

    Replace the latex tube from the CO-filled syringe with a latex syringe cap.  The CO-filled syringe is > 95% pure and ready for experiments.  Allow the apparatus to cool.  The plunger in the Waste syringe may move outward at first because gas generation may continue for several seconds after the test tube is removed from the flame.  The plunger may move inward as the apparatus cools.  Note: It is possible to generate multiple syringefuls of CO(g) by scaling up the amount of reagents used.

    Washing the gases.
        It is not necessary to wash CO(g).

    Preparation of Carbon Monoxide in the Microwave Oven.
        Samples of CO(g) also can be prepared conveniently in a microwave oven.

    Disposal.
        Unwanted samples of CO(g) including the contents of the Waste syringe can be discarded in a fume hood or out of doors.  The liquid remaining in the test tube is partially hydrated H2SO4 which can be dissolved by adding about 10-mL water to the test tube and discarded as acidic wastes.  The test tubes can be reused unless they have been damaged.
     
     
     
    Experiment 1. Blue Jets!  Combustion of CO(g) with a Blue Flame.
    Equipment:
    • Candle (such as a birthday candle supported by a one-holed rubber stopper)
    • 15 cm piece of latex tubing
    • glass disposable pipet
    • pickle jar
    Chemicals:
    • CO(g), 60-mL, several syringefuls
         A burning candle produces a flame that has a region of blue near its base.  This is the color produced when CO burns.  In this experiment we will burn samples of pure CO and observe this blue flame.
         Fit a 15 cm piece of latex tubing into a pipet as shown in Figure 3. It should make a snug fit.  Generate a syringeful of CO(g) as described above.  Replace the syringe cap with the latex tube/glass pipet.

    Figure 3.
     


    In Part B, below, CO(g) burns from a pipet tip with a blue color.  (5-second time exposure taken in dark)

    Part A. While holding the end of the pipet 2 - 3 cm from a candle flame, discharge 30 mL CO over a period of 10 seconds through the flame.  A jet of blue fire should appear on the opposite side of the candle.

    Part B. While holding the end of the pipet <1 cm from the flame, slowly discharge CO(g) near the flame in order to ignite the pipet tip.  It will burn with a gentle blue flame which can be sustained by carefully discharging the CO at a slow rate.

    Part C. Place a candle in a large (> 1 L) vessel that can be sealed such as a pickle jar or a desiccator.  Light the candle and cover the vessel, creating a closed system.  Darken the room.  The candle flame will diminish in size and lose it's characteristic yellow color as the O2(g) is depleted.  As the flame becomes smaller, note the increased size of the blue region especially near the lower part of the flame.  The blue color is attributed to the combustion of CO(g) which replaces CO2 as the dominant product of combustion and is itself combustible.
     
     

    Experiment 2. Wimpy Soap Bubble Explosions and Wimpy Rockets.
    Equipment:

    Chemicals:     Generate a syringe filled with O2(g).  Generate a syringe of CO(g).  Transfer CO(g) and O2(g) to a clean, dry third syringe with the aid of a latex tube.  A 2:1 volume ratio of CO(g) and O2(g) gives the best results because it follows the stoichiometry for the reaction:

    CO(g) + 1/2 O2(g)  CO2(g) DH = -283.0 kJ

    This mixture can be 'exploded':  (a) in the form of soap bubbles similar to Experiment 5 of the Oxygen Chapter   or (b) with the use of a piezoelectric igniter as described in Experiment 6 of the Oxygen Chapter. The 'explosions' are mild.  The rocket, for example, produces a bright flash of light but only travels a few dm.  Other gas mixtures will not leave the launcher but do produce a flash of light.  Exploding various gas mixtures such as C2H2/O2, H2/O2, and CO/O2, would provide a useful comparison and reveal the relative reactivities of these gases.  (See: General information on successfully filling and launching rockets.)  (See: Instructions for the assembly of a piezoelectric sparking device — needed for launching the rockets.)
     
     

    Experiment 3. Quantification of Carbon Monoxide.  Reaction with CuCl(aq).
    Equipment:

    Chemicals:     Solutions of cuprous chloride react with carbon monoxide to form water soluble Cu(CO)Cl(H2O)2:

    CuCl(aq) + CO  Cu(CO)Cl(H2O)2

    This reaction allows for the quantification of CO(g) in gas mixtures.

    Cuprous Chloride Solution.
        Prepare a stock solution of 1.6 M CuCl(aq) in 3 M HCl.  To prepare 100-mL of the solution, prepare 100-mL of 3 M HCl by diluting 25-mL concentrated HCl to 100-mL with distilled water.  To this solution, dissolve 16-g anhydrous cuprous chloride, CuCl.  The solution will be deep forest green in color.  This solution will react with CO(g) in a 1:1 volume ratio: 1-mL solution will react with 1-mL CO.

    Part A. Quantification.
        Prepare a syringe filled with 30-mL pure CO(g).  To this syringe suction in 30-mL 1.6 M CuCl(aq) solution.  Attach the syringe cap and shake the contents vigorously.  Within 30 s the CO will have completely reacted with the solution.  Vigorous shaking is necessary because CO(g) is nearly insoluble in water.  The amount of gas that did not dissolve in the solution represents gases other than CO.  For quantification purposes, record the volume of gas originally present by noting the position of the plunger's rubber seal.  Record the volume of gas again after the reaction is over.  The volume of CO(g) originally present is equal to the difference in these two values.

    Part B. Color of Complex.
        In order to observe the color of the complex Cu(CO)Cl(H2O)2, repeat the reaction above using 30-mL 0.4 M CuCl(aq) solution (prepared by dilution the stock solution with water in a ratio of 1:3).  Under these conditions, the complex can be observed to have a blue-green color.

    from left:
      (a) syringe containing CO(g);
      (b) immediately after CuCl(aq) is drawn into syringe;
      (c) after shaking -- all of the CO reacts leaving air
      (d) dilution shows the color of Cu(CO)Cl(H2O)2

     

    Experiment 4.  Carbon Monoxide Detectors.
    Equipment:
    • Carbon monoxide detector
    • 1 gallon (4-L) sealable (air-tight) plastic bag
    • 5-cm length of latex tubing
    Chemicals:
    • CO(g), 10-mL
       Carbon monoxide detectors are designed to sound a warning when CO(g) concentrations exceed a certain level for a sustained period of time.  This level is between 30 - 100 ppm.  In order to put these levels in perspective, consider that one syringeful of CO(g) discharged into 1 cubic meter of air produces a CO concentration that averages 50 ppm.   This equals the maximum allowable level of continuous exposure for eight hour periods according to the USA's Occupational Safety and Health Administration (OSHA).  A sustained level of 200 ppm will produce a slight headache, dizziness, fatigue and nausea after 2 - 3 hours.

    Figure 4.

        You will need 5 mL CO for this experiment.  It is advisable to know how to reset the alarm prior to performing this demonstration.  Place a digital CO(g) detector in a 1 gallon (4-L) sealable (air-tight) plastic bag and zip shut with plenty of air locked inside.  Plug the device into the electrical service by pushing the prongs through the plastic bag.  Poke asmall hole with a pencil and work the latex tube through the hole.  Connect the tube to a syringe of CO(g) and slowly inject 1 - 5 mL of CO(g) into the bag as shown in Figure 4.  Most detectors need about three minutes to register CO(g) so the display will not change right away.  The level of CO should be 250 ppm for 1-mL CO(g) diluted into 4-L air.
     
     
     
    Experiment 5A. Reduction of CuO with CO(g)
    Equipment:
    • several 60-mL plastic syringes with a LuerLOK fitting
    • Latex LuerLOK syringe cap fittings
    • one piece, latex tubing, 1/8-inch (3.175 mm) ID, 5 cm lengths
    • 18 x 150 mm test tube
    • glass pipet, preferably long-stem
    • ring stand and suitable clamp to pipet
    • small Bunsen burner
    • matches or a lighter
    Chemicals:
    • CO(g), 60-mL
    • 0.5-g copper turnings or copper wool

    Figure 5.
        Carbon monoxide is well known for its ability to function as a reducing agent.  Metal oxides can be reduced to the element with CO(g).  Several important industrial metallurgical processes, including the production of iron and steel in the blast furnace, are based on this reaction.  This reaction demonstrates carbon monoxide's ability to function in this regard.

        Start by constructing the reaction chamber.  With the assistance of the wire tamping tool provided, push copper wool (from a grocery store Chore Boy cleaning pad - without soap) into the glass pipet as shown in Figure 5.

         You will need a syringe filled with CO and a second syringe filled with air before you proceed.  Connect the air-filled syringe to the pipet with a short (3 cm) connecting tube.  Heat the test tube just below the copper for a few seconds with a gentle burner flame.  The copper will begin to darken.  Note how the copper becomes black due to CuO:

    2 Cu(s) + O2(g)   2 CuO(s)

         Attach the CO(g) syringe as shown in the figure and slowly pass the CO(g) through system.  The characteristic shiny metallic orange color of copper will immediately return upon exposure to CO(g):

    CuO(s) + CO(g)  2 Cu(s) + CO2(g)

    This oxidation/reduction process can be repeated over and over.  The gas mixture collected contains CO2(g) which can be qualitatively characterized with lime water.
     

    Initially: Pure Cu in test tube oxidizes to black CuO in the presence of air. 

    Still at elevated temperatures, carbon monoxide is passed through the CuO-coated copper wool instantly reforming shiny copper metal.

     
     
     
    Experiment 5B. Quantitative Reduction of CuO with CO(g)
    Equipment:
    • several 60-mL plastic syringes with a LuerLOK fitting
    • Latex LuerLOK syringe cap fittings
    • two pieces, latex tubing, 1/8-inch (3.175 mm) ID, 5 cm lengths
    • two-hole #1 stopper
    • 18 x 150 mm test tube
    • glass tubing, suitable diameter to form a snug fit in hole of stopper, 2-cm
    • glass tubing, suitable diameter to form a snug fit in hole of stopper, 2-cm shorter than test tube (approximately 13-cm)
    • ring stand and three suitable clamps to hold test tube and syringes
    • small Bunsen burner
    • matches or a lighter
    Chemicals:
    • CO(g), 60-mL
    • 2-g copper turnings or copper wool
    • 5-g powdered CuO(s)
     

    Figure 5.
        Carbon monoxide is well known for its ability to function as a reducing agent.  Metal oxides can be reduced to the element with CO(g).  Several important industrial metallurgical processes, including the production of iron and steel in the blast furnace, are based on this reaction.  This reaction demonstrates carbon monoxide's ability to function in this regard.

        Assemble the apparatus shown in Figure 5.  The 120 x 15 mm test tube fitted with a suitable (#1) two-hole stopper.  The glass tube connected to the CO-syringe goes to within a few mm of the bottom of the test tube.  Wrap 2-g copper turnings or copper wool tightly around the long glass CO delivery tube.  (We use pieces of copper scouring pads sold in grocery stores.)  Begin to insert the wrapped copper turnings into the test tube while maintaining the position of the glass tube through the copper.  A wire or glass rod is useful if pushing the copper into the position shown in the figure.  Seat the rubber stopper very firmly into position to make sure it will seat properly.

        Remove the stopper  just far enough to add about 5-g powdered CuO(s) to the test tube.  The intensely black powder will gather in the copper turnings.  Very little of it should make it to the bottom of the test tube where it could potentially clog the glass CO delivery tube.  Reposition the stopper firmly into the test tube as before.  Generate two syringes of CO(g).  Pass the CO through the system at a rate of about 60-mL/min.  Discard the first 25-mL of gas collected because it is mostly air.  After the first CO(g) syringe is spent, switch to the second.  Continue to collect gas until 60-mL has been collected.  This gas  is almost entirely CO2.  Remove the heat.

        The CO2-content of the syringe can be quantified by reaction with NaOH.  Draw 10-mL of 3 M NaOH(aq), or 5-mL 6 M NaOH into filled gas-collection syringe.  Immediately fit the LuerLOK with a syringe cap.  Shake the syringe.  The plunger will move inward as the CO2(g) reacts with the aqueous NaOH(aq) forming NaHCO3 and/or Na2CO3.  The reaction is:

    2 NaOH(aq) + CO2(g)  Na2CO3(aq) + H2O(l)

    The amount of gas that remains represents non-CO2 gases, including air and unreacted CO.  We have achieved >90% conversion to CO2.
     

    Experiment 6. Carbon Monoxide Poisoning.
    Equipment:

    Chemicals:    Carbon monoxide is toxic.  It binds to hemoglobin about 300 times better than oxygen.  This disables the ability of hemoglobin to carry oxygen to tissues.  In the past, it was possible to perform experiments on samples of human blood.  These days this practice is inadvisable and possibly illegal due to the risks associated with blood-borne diseases.  Nevertheless, it is possible to observe the bright red color due to the CO-hemoglobin complex by using the red meat juices that soak into the absorbent pads provided in grocery store packages of meat.
         Obtain an absorbent pad from a package of fresh beef, pork or poultry.  It is necessary that the pad be soaked with red meat juices.  Lay the pad flat in a plastic bag and freeze for easier handling.  While frozen, cut the pad into strips that will fit into test tubes.  Keep the strips frozen.  Fill a series of stoppered test tubes with various gases such as N2, O2, air, and CO.  Place one frozen strip in each test tube.  Place the test tubes in a rack and store them at room temperature.  Observe the test tubes over the next hour and over night.  The sample in the CO atmosphere will become very bright red.  The others will become gray.  Discard all samples without handling.

    Juice absorbent pads from fresh beef after two hours exposure to oxygen (left), air (middle), and carbon monoxide (right)

    Experiment 7. Reduction of Palladium and Silver Ions with Carbon Monoxide
    Equipment:

    Chemicals:    In Experiment 5 we saw the ability of CO(g) to function as an reducing agent.  Aqueous solutions of metal ions can also be reduced by CO(g) even though the gas is only sparingly soluble in water.  Solutions of 0.01 M PdCl2(aq) form black metallic elemental Pd(s), within minutes of exposure to CO(g).  The reaction takes place at the surface where CO's limited solubility in water allows interaction with the metal ions.  The reaction can be carried out in a disposable plastic cup in a sealable (air-tight) plastic bag.  More concentrated Pd+2(aq) solutions (0.5 M) form a shiny metallic surface that looks similar to nickel.  The clear aqueous solution beneath the surface is acidic as expected by the balanced oxidation-reduction reaction:

    Pd+2(aq) + CO(g) + H2O(l)  Pd(s) + CO2(aq) + 2 H+(aq)

    This reaction is used by medical examiners to test for the presence of CO in samples of blood from individuals suspected of CO-poisoning.  The appearance of a metallic luster of palladium confirms the presence of CO.

         Solutions of 0.1 M AgNO3 are not reduced by CO(g) unless the diamminesilver(I) complex [Ag(NH3)2]NO3 is first formed.  Dissolve 1 g AgNO3(s) in 50-mL distilled water and slowly add concentrated ammonium hydroxide solution.  A brown precipitate will initially form and then disappear as more (2 - 3 mL) ammonium hydroxide is added.  The clear, colorless solution of Ag(NH3)2+ complex will react with CO(g) as described for Pd+2(aq).  The reaction is:

    2 Ag(NH3)2+(aq) + CO(g) + H2O(l)   2 Ag(s) + CO2(aq) + 2 NH4+(aq)


    This curious effect was made by the reduction of Pd+2 as described above.
    Subtle vibrations on the countertop caused the crystals to migrate
    into the center of the plastic cup.  PhotoShop was used to
    duplicate the image, creating a "pair of eyes"!









    Experiment 8. Reaction Between Carbon Monoxide and KMnO4
    Equipment:

    Chemicals:      Carbon monoxide reduces dilute solutions KMnO4 to produce colorless Mn+2.  Transfer about 3 mL of a faintly purple (1 x 10-4 M) KMnO4 solution to a large test tube.  With the aid of a latex tube equipped to the syringe, fill the test tube with CO(g) and stopper.  Upon shaking the test tube, the solution will slowly lose its pink color as the permanganate is reduced.
     
     

    Experiment 9. Catalytic Converters and Your Car
    Equipment:

    Chemicals:  The catalytic converter on your car is designed to reduce the amount of carbon monoxide, nitrogen oxides (NO and NO2), and unburned hydrocarbons that leave the tail pipe.  The catalyzed oxidation of CO involves oxygen from the air:

    2 CO(g) + O2(g)  2 CO2(g)

      This experiment requires the Gas Reaction Catalyst Tube which is sold by Educational Innovations has specifically designed a for these microscale gas chemistry experiments.  The catalyst is housed in a glass tube as shown in Figure 12. 6

    Figure 12.6 Gas Reaction Catalyst Tube, shown attached to two syringes.

         The assembled apparatus is shown in Figure 12.6.  The syringe on the left contains the reagent gas mixture ready to be passed though the catalyst.  A 2-cm length of latex tubing connects the syringe to the tubing.  To the right of the catalyst tube is the receiver syringe, also connected by latex tubing.  The plunger of the receiver syringe must be able to move freely in the syringe barrel.  This is assured by lubricating the black rubber plunger diaphragm.  Two ring stands and clamps, not shown, hold the two syringes in the appropriate position above the burner's flame.  The clamps should not hold the syringes too tightly, and should allow for free rotation of the syringes and catalyst tube for even heating.

         Fill the reagent syringe with 40 mL air (0.34 mmol O2) and 20 mL carbon monoxide (0.82 mmol.)  Cap the syringe and allow the gases to mix for several minutes.  Connect the reagent syringe to the catalyst tube and assemble the apparatus as shown in the figure.  Pass about 10 mL of gas mixture through the catalyst tube to (a) check for leaks, (b) determine that the plunger in the receiver flask moves freely; and (c) displace air (or previous gas mixtures) from the catalyst tube.  (Option: Remove the receiver syringe from the catalyst tube, discharge the 10-mL air from the receiver syringe and reconnect to the catalyst tube.)  Heat the catalyst tube evenly on all sides for a total of about 30 seconds.  (CAUTION: Heat from a Bunsen burner flame is capable of softening the glass portion of the catalyst tube.  When the glass is soft, it is susceptible to deformations and even "blow holes" if the pressure inside the system is increased by moving the plunger of the syringe.  To prevent overheating the glass, use only a cool Bunsen burner flame.  Minimize the amount of air used so that the flame has a soft, ill-defined blue inner cone.  Position the catalyst tube at least 1 cm above the tip of the inner cone.  Watch for traces of red, orange or yellow in the flame above the catalyst tube.  These colors indicate that the glass is softening.  If this should happen, remove the flame and adjust the flame.)
     Slowly pass about half of the CO/air reagent gas mixture through the catalyst tube over the course of about 30 seconds.  Be alert for problems — the volume of gases collected in the receiver syringe should almost equal the volume decrease in the reagent syringe.  After half of the gas mixture has been passed through the catalyst tube, remove the heat.  Remove both syringes and cap them with latex syringe caps.  Label the syringes with a marker pen.

     Qualitative test for the presence of CO2(g) is possible by the Limewater test for CO2:  Place 10 mL limewater in a 15 x 180 mm test tube.  Equip the syringe with a 15 cm length of latex tubing.  Discharge 10 - 20 mL of the gas above the limewater solution.  Remove the syringe and tubing.  Stopper the solution and shake to mix gaseous layer with limewater solution.  A white suspension of calcium carbonate confirms the presence of carbon dioxide.   CO2:

    CO2(g) + Ca(OH)2(aq)   CaCO3(s) + H2O(l)

     Other catalytic reactions take place in your car's catalytic converter as well.  These reactions will be discussed in a later chapter.
     
    Catalytic converter from a truck (cars have similar units).  Below: Actual converter cut in half exposing the ceramic honeycomb coated with catalyst.  Top right: Band saw was used to cut honeycomb in half.  Bottom right: A small piece, as described in the experiment, is cut to fit inside of a test tube.
     









    Experiment 10.  Demonstrating the Water-Gas Shift Reaction.
    Equipment:

    Chemicals:


         'Water-gas' is the name given to a mixture of H2 and CO produced by passing steam over red-hot coke:

    C(g) + H2O(g)   CO(g) + H2(g)

    The CO/H2 mixture can be burned directly as a fuel or reacted further at a lower temperature to convert the CO(g) to more desired products by means of the so-called the 'water-gas shift' reaction:

    CO(g) + H2O(g)   CO2(g) + H2(g) DH = -41.0 kJ  DS = -42.3 J/K

    The water-gas shift reaction, which we will demonstrate in this experiment, is catalyzed by iron or Fe3O4 at elevated temperatures.

         The apparatus used for this reaction is shown in Figure 6.  The 15 x 180 mm test tube is fitted with a 2-hole stopper equipped with a long glass tube that extends to 2-mm from the bottom of the test tube and a shorter glass tube.  The latter is connected to the gas collection syringe by a short piece of latex tubing.  An additional gas collection syringe is necessary.  Lubricate the plungers of the gas collection syringes; they must move easily.  Steel wool comes coated with a protective film to reduce oxidation.  Unfold a 4 - 5 g piece of fine (#00) steel wool.  Hold the steel wool with crucible tongs and ignite it from the bottom with a small burner (butane lighter) flame.  The organic film will burn with the production of considerable smoke, leaving behind Fe3O4.  Remove the stopper from the test tube just far enough to wrap a 2.0-g piece of the burned steel wool around the long glass tube and work it down into the test tube.  The steel wool should be densely packed.  Re-seat the stopper.  The glass tube should run through the steel wool as shown in the figure.  With a pipet, add 1-mL H2O(l) to the test tube via the long glass tube.  The glass tube should be under the surface of the water.

         Generate two syringefuls of CO(g).  Push 30-mL CO through the system via the long glass tube.  This purges the system of air.  Switch syringes so that a full syringe of CO(g) is available for the reaction.  Heat the test tube to near its softening temperature (ca. 400 oC) directly below the steel wool (and not the water).  Radiant heat will cause the water to start to boil.  When the water begins to boil, slowly deliver the CO(g) from the syringe.  As it bubbles through the water, it sweeps H2O(g) with it through the steel wool, where the reaction is catalyzed.  In order to prevent steam burns, do not switch syringes while the system is hot.

          The gas collection syringe contains CO2(g) and H2(g) along with unreacted CO(g) and H2O(g, l).  The contents of the syringes can be qualitatively tested for CO2(g) using limewater.

         As a 'control', repeat the experiment without heating the catalyst.  No CaCO3(s) will appear in the limewater test.
     
     

     


    Figure 6.


    Photograph of assembly shown in Figure 8.

     


    Clean-up and Storage.

        At the end of the experiments, wipe excess lubricant off of rubber diaphragm. Clean all syringe parts (including the diaphragm), caps and tubing with soap and water.  Use plenty of soap to remove oil from the rubber seal.  This extends the life of the plunger.  It may be necessary to use a 3-cm diameter brush to clean the inside of the barrel.  Rinse all parts with distilled water.  Be careful with the small parts because they can easily be lost down the drain. Important: Store plunger out of barrel.



     
     
    This article first appeared in Chem13 News in March, 1999.  The authors of the original Chem13 article are: 

    From the Department of Chemistry, Creighton University, Omaha, Nebraska 68178 USA:

    • Bruce Mattson*, faculty member, principal investigator
    • Michael Anderson, faculty member, co-principal investigator
    • Rebecca Catahan, undergraduate chemistry major,  graduated May, 2000, currently in PhD program in chemistry at University of North Carolina
    • Paras Khandhar, undergraduate chemistry major, will graduate May, 2001, plans to go to medical school
    Also from Creighton University:
       
    • Maneesh Bansal, undergraduate student, currently a health administration major, will graduate May, 2001, plans to go to medical school
    • Andrew Mattson, undergraduate student, currently an English major with journalism concentration, plans to graduate in December, 2001
    • Anand Rajani, undergraduate student, currently a psychology major, plans to graduate in May, 2001 and go to medical school


    Viktor Obendrauf, Bundesoberstufenrealgymnasium Feldbach, Austria

    Rimantas Vaitkus, Department of Chemistry, Vilnius Pedagogical University, 2034 Vilnius, Lithuania

    *Author to whom correspondence should be addressed.  E-Mail: xenon@creighton.edu


     

    Some of the CO-researchers: from left: Maneesh Bansal, Andrew Mattson, Anand Rajani and Rebecca Catahan.


    from left: Bruce Mattson, Andrew Mattson, Anand Rajani and Rebecca Catahan.

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    (This page last updated 29 January 2002)


    from left: Anand Rajani and Paras Khandhar