Download Calorimetry

Calorimetry
Copy and complete the following data table into your Lab Notebook:
Food Type
Marshmallow
Cheetos
Walnuts
Initial mass of food and holder
Final mass of food and holder
Mass of food burned
Mass of water and can
Mass of empty can
Mass of water
Final H2O temperature, t2 (high)
Initial H2O temperature, t1 (low)
Temperature change, ∆ T
Energy absorbed by water
Energy content of food sample ∆ H, in kJ/g
Procedure:
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Carefully place the first food item on an opened paperclip, so that it will not fall off. Then, stick the other end of the paper
clip into a cork. (see teacher demo) Record the mass of the sample and the cork.
Determine and record the mass of the empty soda can. Add 100 mL of tap water to it and record its mass again.
Use ring-stand, rind, and stirring rod to suspend the soda can over your food sample. Secure a thermometer above the
apparatus. Record the temperature pf the water. Do NOT allow the thermometer to touch the bottom of the can.)
Place the food sample under the can and carefully ignite the sample from the bottom with a butane lighter.
Allow the water to be heated until the sample stops burning. Record the highest temperature reading.
Record the mass of the burned food sample and cork again.
Repeat the procedure for each other food source. You will need to replace the water in the can each time.
Process Data: Show all calculations.
1. Find the mass of water heated for each sample.
2. Find the change in temperature for each sample.
3. Calculate the heat absorbed by the water, E, using the equation: E =(CpH2O) (m) (∆T)
4. Convert each heat into kJ.
5. Find the mass of each food sample burned.
6. Calculate ∆ 𝑯 for each food sample: ∆ 𝑯 = E absorbed by the water
grams of burned food
Questions:
1. Which has the highest energy content? Lowest?
2. Two of the foods in the experiment have high fat content and the one has high carbohydrate content. Based on your results,
what generalization can you make about the relative energy content of fats and carbohydrates?
3. Describe two possible sources of error in your experiment and an explanation of how the experiment might be better
designed to minimize these errors.
Conclusion:
Write a brief paragraph to explain what you did and what you learned. Include your results and reasons for sources of error.