How is the caloric value of a food sample determined

Lab Report

Final Report

Exercise 1

CHEM 181 DL1 Caloric Content of Food

Similar: constant volume and temperature

Different: caught fire outside of water, not enclosed, no stirring of water

1. Compare the calorimeter that you built to a bomb calorimeter. How are they similar and dif f erent?

I thought this way a fairly simple at home way to measure calories as opposed to bomb colorimeters which are harder to make than the one I made. An error that I think occurred was that the heat started to come out of the tent so the heat started to become lost. If I had unlimited expenses I would probably try to recreate a real calorimeter instead of a make shift one.

2. Based on your results, was this setup a good way to measure Calories as opposed to a bomb calorimeter? What types of experimental error may have occurred with this experiment? How might you design this setup dif f erently if you had unlimited expenses for materials?

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I thought this way a fairly simple at home way to measure calories as opposed to bomb colorimeters which are harder to make than the one I made. An error that I think occurred was that the heat started to come out of the tent so the heat started to become lost. If I had unlimited expenses I would probably try to recreate a real calorimeter instead of a make shift one.

3. Based on how each food burned, which food would be the best to use for a fuel that has a steady f lame and might burn for a long t ime? What was the composit ion of this food (which macromolecule was it mostly composed of )? How does this relate to the way that the human body utilizes this type of macromolecule as fuel?

I think this is because protein in the body is not used for energy immediately, it is stored and used later.

4. Although protein was part of the composit ion of the foods in this experiment, it was not the main macromolecule component of any of the foods. Why do you think a food consisting primarily of protein was omitted f rom these tests, based on what you learned about the way the fuel is "burned" in the body?

The marshmallow had the least amount of calories per gram. This is true because there’s no fat.

5. Using your data, which food had the most amount of kilocalories per gram? Based on what you learned about the structure of each macromolecule, why is this true?

The numbers were not the same. There might be some discrepancy because usually companies will round up when they are making calorie labels.

6. When you determined the amount of estimated Calories in the foods based on Atwater f actors using the amounts of each macromolecule in the food, did you get the same number as what was listed as the amount of Calories per serving on the nutrit ion label? If not, why do you think there might be some discrepancy?

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Data Table 1: Mass of the Water

Data Table 2: Caloric Calculations

Walnut

Mass of the Water (g)

Marshmallow

Mass of the Water (g)

Tortilla chip

Mass of the Water (g)

45.8

44.7

49.2

Food Item Description: Walnut

Mass of food, cup, and clip - initial (g)

Mass of food, cup, and clip - final (g)

Mass of burned food (g)

Observations of Flame (intensity, length of time burning, etc.)

Water temp - initial °C

Water temp - final °C

Change in temp (ΔT) °C

Energy released (Q) (kcal)

Energy released per gram (Q/m) (kcal/g)

Energy Estimated on Package (kcal/g)

Percent Difference

29.1

28.9

0.2

burned very quickly

31

35.6

4.6

1.2

0.48

5.7

81%

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Determination of Calories according to Atwater Factors (kcal/g)

Food Item Description: Marshmallow (Jumbo)

Mass of food, cup, and clip - initial (g)

Mass of food, cup, and clip - final (g)

Mass of burned food (g)

Observations of Flame (intensity, length of time burning, etc.)

Water temp - initial °C

Water temp - final °C

Change in temp (ΔT) °C

Energy released (Q) (kcal)

Energy released per gram (Q/m) (kcal/g)

Energy Estimated on Package (kcal/g)

Percent Difference

Determination of Calories according to Atwater Factors (kcal/g)

Food Item Description: Tortilla Chip

Mass of food, cup, and clip - initial (g)

Mass of food, cup, and clip - final (g)

Mass of burned food (g)

Observations of Flame (intensity, length of time burning, etc.)

6.1

34.1

33.6

0.5

turned black, but took 8 minutes

28.1

32.2

4.1

0.35

0.05

1.7

80%

3.3

29.6

29.3

0.25

very quickly took 60 second on the flame

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Photo 1: Nutritional Labels

Water temp - initial °C

Water temp - final °C

Change in temp (ΔT) °C

Energy released (Q) (kcal)

Energy released per gram (Q/m) (kcal/g)

Energy Estimated on Package (kcal/g)

Percent Difference

Determination of Calories according to Atwater Factors (kcal/g)

31.1

35.2

4

0.8

4.8

5.4

85%

5.5