Flaming Snowball - Gabrielle _ Lisa by stariya

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									                   Discrepant Event: Flaming Snowball
                                                                       Gabrielle Alberni
                                                                           Lynn Peters

Description: We will be mixing a solution containing Calcium Acetate dissolved in
water with a liquid solution of 95% Ethanol then observing what is produced.

Curriculum:
   Senior 1:         S1-2-11        Properties of Substances
                      S1-2-12        Physical versus chemical changes
                      S1-2-13        Determine the indicators of chemical changes
                      S1-2-14        Combustion

      Senior 2:      S2-2-05        Conservation of Mass
                      S2-2-06        Balancing equations
                      S2-2-07        Classify chemical reactions

      Senior 3:      C11-3          Chemical Reactions
                      C11-4          Solutions: Polar vs. Non-Polar

Materials:
   2 * 500 ml beaker
   300 ml beaker
   Calcium Acetate
   95% Ethanol
   Sink (nearby)
   Water
   Two metal bins (1 empty, 1 with water)
   Fire Extinguisher
   Paper Towel
   Matches
   Marshmallows and roasting sticks

Procedure:
    First, we will prepare two solutions in separate beakers. Solution A will contain
      50ml of water and 6g of Calcium Acetate. Mix the two until most of the Calcium
      Acetate is dissolved in the water and the solution looks clear. Solution B is 150ml
      of 95% Ethanol in a 500ml beaker.
    Now we will ask the class if they can predict what will happen when we mix the
      two solutions. Students can talk amongst each other and write down their
      prediction.
    Pour solution A into solution B and observe. Immediately, we will see that a gel
      has formed inside the beaker
    The next step should be performed near a sink. We will remove the material from
      the beaker then shape into a ball. This will be done over a sink to catch the excess
      ethanol.
    After handling the “snowball” wash hands well, then make sure they are dried as
      well.
        Student volunteers can touch the “snowball” to feel the texture and temperature of
         it.
        Place the ball in an empty metal bin, or something that is safe and not flammable,
         and then light it with a match. Having the classroom lights out will be the best
         way to see the flame.
        The first demonstration will be to pick up the flaming ball and explain how it
         feels. Make sure you dip your hands in the tub of water first so it doesn’t burn
         hands.
        Student volunteers will be asked to handle the burning ball and explain how it
         feels in terms of temperature. Ethanol burns at a lower temperature than other
         substances which allows for it to be held while burning.
        The second demonstration is to roast a marshmallow using the flaming ball. This
         will show the whole class that the “flaming snowball” is giving off heat.
        At the end of the presentation, the flame will be extinguished by covering it with a
         clean dry beaker.

Principles:

A physical change occurs when liquid ethanol is poured into the clear saturated calcium
acetate solution. This forms a solid gel. This gel is similar to “Sterno”, a gel which is
used as fuel in portable cooking stoves.

The calcium acetate molecules are polar and readily dissolve in the polar water
molecules. When the saturated calcium acetate (polar) is mixed with the ethanol (non-
polar), the acetate molecules precipitate and form a gel. This gel consists of a liquid
(alcohol) dispersed throughout a solid (acetate). The “snowball” consists of calcium
hydroxide (Ca(OH)2) with ethanol (CH3CH2OH) in it. Once ignited, the ethanol reacts
with oxygen to create a flame. Note that the flame is fairly clear and thus to prove that
there is indeed a flame you could for example roast a marshmallow. If the gel were
placed into an empty tuna can, and ignited, it would produce enough heat to fry anything
for a period of about 22 minutes.

Gel formation:




                   +                       


       Liquid              Liquid                  Liquid (top layer) + Solid (bottom layer)


(CH3COO)2Ca +          2 CH3CH2OH             2 CH3COOCH2CH3 + Ca(OH)2
Calcium Acetate           Ethanol                Ethyl Ethanoate Calcium Hydroxide
Combustion Reaction:




2 CH3CH2OH +          6 O2                                          + 4 CO2 + 6 H2O
     Ethanol
(in the snowball)


This event is likely to create disequilibrium because the gel looks like a “snowball” that
is lite on fire. This demonstration is also discrepent in the fact that when the saturated
calcium acetate solution is mixed with the ethanol it forms a gel. (liquid + liquid  solid)

Safety Concerns:
    Ethanol is very flammable so make sure there isn’t anything that can catch on fire
       nearby.
    Do experiment with a partner so handling is easier, and one is always cleaning up
       to keep area safe.
    Don’t breathe in the Calcium Acetate directly.
    When removing jelly substance from the beaker, do it over a sink so the excess
       ethanol isn’t present in the experiment working area.
    Make sure the surface where the “snowball” will be lit is completely dry.
    Hold the flaming snowball with clean hands only and make sure there’s no
       ethanol on your skin from previous steps.
    Have a metal container with water nearby to wet hands before handling the
       flaming snowball.
    Be careful while handling the snowball because if dropped, it will break into
       many flaming pieces.
    Distinguish the flame before it gets very hot.

References:

      http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA2/CCAMAIN.HTM
      http://www.wikihow.com/Make-a-Flaming-California-Snowball
Experiment: Flaming Snowball
Name: _____________________

								
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