Safety Precautions:  Ethyl alcohol is a flammable liquid and a dangerous fire risk.  Have a large beaker to cover the fire or an ABC class fire extinguisher available during this activity.  

Materials
Calcium acetate, monohydrate, Ca(C2H3O2)2 H2O, 3 g Ethyl alcohol, 95%, CH3CH2OH, 75 mL Sodium chloride, NaCl, pinch Graduated cylinder, 100-mL Fire extinguisher, ABC class Matches Balance Beaker, 250-mL Spatula Evaporating dish or small beaker, Pyrex Stirring rod or wood stick

        Procedure

Prepare a SATURATED calcium acetate solution

1. Weigh out 3 grams of calcium acetate in a 250-mL beaker.

2. Measure out 10 mL of water (tap wate is fine), and add it to the calcium acetate.  Stir to dissolve most of the solid (not all of the solid will dissolve).

3. Add a pinch of sodium chloride to the calcium acetate solution and stir.

Prepare STERNO

1. Measure 75 mL of ethyl alcohol using a graduated cylinder and transfer it to the beaker containing the calcium acetate solution.  The gel will form as soon as the alcohol is added.  Do not stir the mixture.

2. Using a spatula, transfer the gel into the evaporating dish.

3. Place the evaporating dish on a non-flammable ceramic fiber square or tile and away from all combustible materials.

4. Use a match to carefully light the gel.  Turning off the lights will make the flame more noticeable.  Notice the formation of calcium carbonate on the inside of the evaporating dish.  The sodium chloride added to the solution makes the flame yellow and therefore more visible.

5. The evaporating dish will get extremely hot, so use caution and do not handle until is has cooled completely.

6. Wash hands, work area, and equipment thoroughly when finished.

[An alternative is to grind a piece of chalk (calcium carbonate) and add to 25 mL of household vinegar.  Boil solution to produce saturated calcium acetate.]

Discussion

Sterno is a commercial product used in many cafeteria and banquet serving lines.  It is a favorite with restaurants because it provides a reliable, odorless and safe heat source.  Sterno, also called Canned Heat, produces a flame that is relatively small and long lasting.  Since it is a solid, it does not spill.  Another benefit is that is does not evaporate or easily vaporize.  Canned Heat is produces by mixing a concentrated solution of calcium acetate with ethyl alcohol.  As the ethyl alcohol and calcium acetate solution

Source:  Flinn Publication

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