Chemistry Honors Formal Lab
Background: The food that we eat throughout the day has energy for our bodies to use. The food content of food is given in kilocalories, which is 1000 calories, and is often known in Calories. A calorie is the amount of heat, energy, needed to raise the temperature of one gram of water by one degree Celsius. You can measure the calorie content of food by lighting a snack on fire and putting a sample of water above the flame, while allowing the water sample to gain the heat from the fire. The heat absorbed by the water from the flame will raise the temperature of the water. Whatever heat gained by the water was lost by the burning food. This allows us to find energy content of common snack foods in our everyday lives. Purpose: To determine the energy content in various snack foods, and compare results to the manufacturer’s data. Materials:
Assorted snack foods: (pecans, Cheetos, Fritos, Cheez-it, marshmallow, potato chip,Popcorn.) Weigh boats
Wire paper clips
Empty soda can
Ring stand with ring clamp
Safety: Observe and know all the safety rules. Wear goggles. Tie long hair back and take off the loose clothes. Practice caution when working with open flame. Heated items will be hot… handle carefully. Don’t eat any food in the lab.
Prediction: I predict that the marshmallow will contain the highest amount of calories because it contains the most sugar and it is different from all the others in composition.
Hypothesis: If we use a calorimeter to determine the calories in various foods, then the marshmallow will have the highest caloric content because it contains the highest amount of sugar.
1. Before you begin, make sure the ring stand base and your lab benches are covered in aluminum foil and put a glass stir rod between the sodas can to rest on the ring stand base. 2. Place 100 mL of water in the graduated cylinder and put it into the empty soda can. 3. Assume the density of the water is 1g/mL and record the mass of the water in the data table. 4. Take the temperature of the water and put it in the data table. 5. Find the mass of an empty weigh boat and put it in the data table. 6. Get the first mass of the first snack item to be tested and put in the data table. 7. Slowly and peacefully put the snack item on the cork and paper clip stand you constructed, and place it under the can. 8. Place the can with water in it on the ring stand base, so it is exactly 2cm over the snack item. 9. Light the snack item under the can and make sure the flame is all around the can. 10. As soon as the flame dies down, stir the water gently and get the temperature of the water and put it in the data table. 11. Find the temperature change and put it in the data table. 12. Using the tongs and caution, pour the hot water down he sink. 13. To remove the carbon black from the water of the can, wipe it with a wet paper towel. 14. Using the original weigh boat find the new mass of the burnt snack food item. 15. Find the change in mass of the snack food item.
16. Repeat steps 2-14 for the rest of the snack food items. 17. Lastly, clean the carbon black off the can with a moist paper towel.
Food| Mass| Water T1| Water T2| Final Mass| Temp Change| Cheez-it| 1.022g| 20◦ C| 28◦C| 0.054g| 8◦C|
Potato Chip| 1.89g| 20◦C| 29◦C| 0.331g| 9◦C|
Cheetos| 2.056g| 20◦C| 41◦C| 0.281g| 21◦C|
Marshmallow| 7.323g| 22◦C| 29.5◦C| 6.056g| 7.5◦C| Frito| .923g| 22◦C| 30◦C| 0.278g| 8◦C|
Popcorn| 2.001| 20◦C| 30◦C| 0.177g| 10◦C|
Calculations:Calories absorbed by water
1. 100g*1cal/gram◦ C*(28-20)= 800 calories
2. 100g*1cal/gram◦ C*(29-20)=900 calories
3. 100g*1cal/gram◦ C*(41-20)=2100 calories