OBJECTIVE: In this experiment, you will burn several types of nuts and snack foods in order to determine their heat content per gram.
For one team:
HAZARDS: The obvious concern is for burns. Also some students may be allergic to the nuts and/or their burning. Check with the students before proceeding. Some nuts may be substituted or omitted. Black soot will form on the bottom of the can which may stain clothing.
After the nut/food burns completely, record the final temperature of the water, and determine the actual mass of nut/food that has burned. Repeat the procedure, using a different type of nut/food sample.
Using your data for the mass of the water, the mass of the nut that actually burned, and the initial and final temperatures of the water, calculate the heat released per gram of nut/food burned.
DISPOSAL: Discard the ash in the waste basket. Recycle the soda cans.
CALCULATIONS: SHOW ALL WORK USED!!!
The value for kilojoules per gram of nut/food determined by this procedure is generally much lower than the value in the literature, but they are proportionately lower for each type of nut/food tested. Students can be challenged to make a more efficient calorimeter. The operation of a bomb calorimeter can also be explained as a closed system where the food is literally "blown up" and all the heat energy is accounted for. The literature value for the heat content of raw almonds is 28.4 kJ/g, Brazil nuts = 30.1 kJ/g, pecans = 31.6 kJ/g, pistachios = 27.6 kJ/g, black walnuts = 28.6 kJ/g and peanuts = 23.6 kJ/g.
REFERENCE: John Grossman, "How Many Calories Are There In A 230-Calorie Dinner?", Hippocrates, Sept/Oct 1987 (5).
Submitted by Justin Field Chemistry Institute 1988 with modifications by Mark Case, CHEM 6 Team Binder 1995.