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Objective: To determine the heat of combustion of candle wax (cal/g)
Procedure:
1. Hold a lighted match near the base of a candle so that some melted wax falls onto
a 3X5 index card. Immediately push the base of a candle into the melted wax. Hold the
candle there for a moment to fasten it to the card.
2. Determine the combined mass of the candle and index card. Record the value.
3. Carefully measure (to the nearest milliliter) about 100.ml of chilled water. (The chilled
water should be between 10. to 15degree C colder than room temp). Pour the 100.-ml of
chilled water into an empty soft-drink can.
4. Using the tab of the soda can, put a glass rod thru the tab and onto an O-ring attached to
a stand so the soda can is elevated off the base of the stand. Place the candle on the stand base
and change the hieght of the can so that the top of the candlewick is about 2 cm from bottom
of the can.
5. Measure and record both the room temperature and the water temperature.
6. Light the candle. Periodically stir the water as it is heated.
7. Continue heating until the temperature rises as far above room temperature as it was below
room temperature at the start. (i.e. start at 15degC and room temp is 25deg C so you raise temp to 35degC)
8. When the desired temperature is reached, extinguish the candle flame.
9. Continue stirring the water until its temperature stops rising and record the highest Temp.
10. Determine the mass of the cooled candle and index card including all wax dripping.