Honors Chemistry
The Energy of Snack Foods
Name:
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Period:
Background Information:
Food has potential energy stored in the chemical bonds. When we eat food, the potential energy is converted
into chemical energy. All human activity requires “burning” food for energy. The body uses the chemical
energy from foods to maintain body temperature, to contract muscles, and to repair tissues. Any excess
energy is stored as fats. Food energy is often expressed in a unit called a Calorie. There are 4180 J in one
food Calorie.
Not all types of food release the same quantity of energy in calories when they burn or are metabolized.
Whether food is fat, protein, or carbohydrate makes a difference in calorie counting. Most of the energy we
need comes from carbohydrates and fats. Carbohydrates produce 17,000 J/g while fats produce 38,000 J/g.
Proteins produce 17,000J/g. In this experiment you will determine the energy released (in J/g) as various
snack foods (cheese puffs, popcorn, peanuts, marshmallows) burn.
Procedure:
Safety: There will be open flames in the lab. Make sure that your hair and loose clothing is pulled back, so
they do not come in contact with the flames. Wear your goggles at all times. Make sure that all flames are
extinguished before leaving the lab area.
1. You will be testing several types of snack foods in this experiment, including, Teddy Grahams® (honey
and chocolate), cheese puffs, popcorn, and mini-marshmallows.
2. Add 100.0 mL of cold water into an empty, clean metal soft drink can. The density of water is 1.0 g/mL.
Record the mass of water in the can.
3. Measure and record the initial temperature of the water.
4. Attach an S-hook to the top of the soda can. You will now be able to hang the soda can from a ring on a
ring stand.
5. Carefully place the food sample on the holder. Measure and record the mass of the sample and holder
combined.
6. Place the sample under the can. Adjust the height of the ring on the ring stand so the sample is about 2
cm from the bottom of the suspended can.
7. Remove the sample from underneath the can. Light the sample. Once it begins to burn, push the sample
underneath the can. (This prevents the water from being heated by the lighter.)
8. Use a thermometer to stir the water gently as the food burns. Record the highest temperature reached by
the water. The thermometer should not touch the bottom or sides of the can. Calculate and record the
change in temperature.
9. After the sample has finished burning, measure and record the final mass of the sample and holder.
Calculate and record the mass of food burned during the experiment.
10. Empty the water from the can. Wash and dry the outside. Repeat steps 1-8 for the next sample.
Honors Chemistry
The Energy of Snack Foods
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Purpose: What is the purpose of this lab?
Pre-Lab Questions:
1. Suppose 200 g of water increases its temperature from 20°C to 25°C. How much heat did the water
receive? The specific heat of water is 4.18 J/g °C. Show your work and record your answer on the line.
2. One gram of bread produces 12,000 J of energy. How many food Calories is this? Show your work and
record your answer on the line.
3. Use the given energy values to explain why our bodies store excess energy as fats.
Hypothesis:
Which snack food will release the most energy? Explain your prediction.
Data Table:
Food sample
a mH2O (g)
b Tinitial (°C)
c Tfinal (°C)
d ∆T (°C) [c − b]
e mfood, initial (g)
f mfood, final (g)
g ∆mfood (g) [f − e]
Teddy Graham® (honey)
Teddy Graham® (chocolate)
Data Analysis:
1. a. Assume that all of the energy released by the burning food goes into heating the water. Calculate the
heat (q) absorbed by the water. The specific heat of water is 4.18 J/g °C. Show your work in the table
using your cheese puff data. Record your answers for each snack type.
b. Using your heat calculation and the mass of food burned, calculate the energy content (in J/g) of each
snack type. Show your work using your Teddy Graham® (honey) data. Record your answers for each
snack type.
c. Calculate the number of food Calories that are in one gram of each snack type. Show your calculations
using your Teddy Graham® (honey) data. Record your answers for each snack type.
Teddy Graham® Teddy Graham®
Calculation Teddy Graham® (honey) calculations
(honey)
(chocolate)
Heat, q (J)
Energy
content (J/g)
Food
Calories
(Cal/g)
Honors Chemistry
2. a.
b.
c.
d.
3. a.
The Energy of Snack Foods
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Restate your hypothesis.
Was your hypothesis supported or rejected?
Which snack food released the most energy?
Explain why that food released more energy than the other foods tested.
Very light activity, like reading, uses about 7000 J/min. How many minutes of reading could you do
from eating one serving (30 grams, about 24 cookies) of honey Teddy Grahams®? Show your work.
b. If I eat an extra-large box of Teddy Grahams® (about 10.00 oz or 283.5 g) while reading for an hour,
what will happen to the excess energy I’ve consumed?
4. A person of average weight uses about 100 Calories/mile when jogging. How many servings of
chocolate Teddy Grahams® (one serving = 30 grams, about 24 cookies) would you need to provide the
energy required to run one mile? Show your work. Note: 1 J = 0.0002390 Cal; 1 Cal = 4,184 J