Caloric Content of Food Final Report

Chemistry Caloric Content of Food Final Report Test Your Knowledge Match each term to the best description. Consist of hundreds of molecules linked together 1 Proteins 2 Amino acids Contain C, H, amino group, carboxyl group, and a side chain Have a high amount of energy but take more time to break down than 3 Lipids carbohydrates Long chains of linked carbons that have a glyceride backbone and three fatty 4 Triglycerides 5 Carbohydrates acids Simple sugars, starches, and über Use Atwater factors and the provided table to rank the snacks from highest number of calories to lowest number of calories. Snack Fat (g) Pretzels Carbohydrate (g) 0 Potato chips 15 Graham crackers 3 Granola bar 3 Fiber (g) Protein (g 23 23 24 17 1 3 1 3 1 2 1 1 Potato chips Graham crackers Pretzels Granola bar Label the image of the bomb calorimeter. 3 Turbine 2 Water 1 Reactant 4 Thermometer 5 Outer chamber 6 Bomb Match each term to the best description. 1,000 calories 1 Kilocalorie A unit of energy 2 calorie (cal) 3 Dietary Calorie Energy released from food (also called kilocalories) Water is 1.00 cal/g°C 4 Exploration A calorie is the amount of heat necessary to raise the temperature of one gram of water by one degree Celsius (°C). True False A bomb calorimeter is used to measure energy changes in reactions that occur at a constant pressure. True False Proteins are composed of hundreds of small molecules called _____. peptides amino acids über nitrogen Speciüc heat capacity Triglycerides are long chains of linked carbons that have a glycerol backbone and three fatty acids; they can be a component of lipids. True False There are thirty diûerent types of amino acids that can be found in proteins. True False Lipids provide approximately _____ calories per gram. 4 5 8 9 11 Exercise 1 Compare the calorimeter that you built to a bomb calorimeter. How are they similar and diûerent? B I U There are similarities and diûerences when comparing the calorimeter that I built to a bomb calorimeter. The similarities are the constant volume and the temperature. The diûerences are that there is no stirring of the water it is not enclosed. 40 Word(s) 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 diûerently if you had unlimited expenses for materials? B I U 46 Word(s) Based on my results, ultimately it was not a reliable way to measure calories as opposed to a bomb calorimeter. There were experimental errors such as escaping of heat and the overall durability. If I had unlimited expenses for materials I would get a real one. Based on how each food burned, which food would be the best to use for a fuel that has a steady ýame and might burn for a long time? What was the composition 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? B I U 72 Word(s) Based on how each food burned, the chip and the walnut were the best use for a fuel that has a steady ýame and would burn the longest. These items burned for quite some time. I determined that this is because the foods are mostly composed of carbohydrates and fats. This relates to the way that the body utilized this type of macromolecule as fuel because the humans slowly burns them oû. Although protein was part of the composition 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 from these tests, based on what you learned about the way the fuel is "burned" in the body? B I U The reasoning that protein was not used as a main macromolecule in this experiment could be that protein is not immediately < burned= in the body and used for energy. 29 Word(s) 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? B I 30 Word(s) U Based on my data, the marshmallow had the least amount of calories per gram. Based on what I learned, this is true about the structure because there is no fat. When you determined the amount of estimated Calories in the foods based on Atwater factors 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 nutrition label? If not, why do you think there might be some discrepancy? B I 50 Word(s) U The numbers I gathered were not the same. I think there could be some discrepancy because the nutritional label amount of calories may not be an exact amount. This number may be rounded oû. In addition, having a faulty experiment by not utilizing a real calorimeter can aûect the number. Data Table 1: Mass of the Water Walnut Mass of the Water (g) 45.8 Data Table 2: Caloric Calculations Marshmallow 44.7 Tortilla chip 49.2 Food Item Description: Walnut Mass of food, cup, and clip - initial (g) 29.1 Mass of food, cup, and clip - ünal (g) 28.9 Mass of burned food (g) 0.2 Observations of Flame (intensity, length of time burning, etc.) caught on üre quickly and burned for several minutes Water temp - initial °C 31.0 Water temp - ünal °C 35.6 Change in temp (ΔT) °C 4.6 Energy released (Q) (kcal) 1.2 kcal/g Energy released per gram (Q/m) (kcal/g) 6 Energy Estimated on Package (kcal/g) 5.7 kcal/g Percent Diûerence 81 Determination of Calories according to Atwater Factors (kcal/g) 6.1 kcal/g Food Item Description: Marshmallow (Jumbo) Mass of food, cup, and clip - initial (g) 34.1 Mass of food, cup, and clip - ünal (g) 33.6 Mass of burned food (g) 0.5 Observations of Flame (intensity, length of time burning, etc.) caught on üre and burned black and did not burn for more than 15 seconds Water temp - initial °C 28.1 Water temp - ünal °C 32.2 Change in temp (ΔT) °C 4.1 Energy released (Q) (kcal) 0.35 kcal/g Energy released per gram (Q/m) (kcal/g) 0.7 Energy Estimated on Package (kcal/g) 1.7 kcal/g Percent Diûerence 80 Determination of Calories according to Atwater Factors (kcal/g) 3.3 kcal/g Food Item Description: Tortilla Chip Mass of food, cup, and clip - initial (g) 29.6 Mass of food, cup, and clip - ünal (g) 29.3 Mass of burned food (g) 0.25 Observations of Flame (intensity, length of time burning, etc.) caught on üre quickly and burned for about a minute Water temp - initial °C 31.1 Water temp - ünal °C 35.2 Change in temp (ΔT) °C 4.0 Energy released (Q) (kcal) 0.8 kcal/g Energy released per gram (Q/m) (kcal/g) 3.2 Energy Estimated on Package (kcal/g) 5.4 kcal/g Percent Diûerence 85 Determination of Calories according to Atwater Factors (kcal/g) 5.5 kcal/g Photo 1: Nutritional Labels Competency Review What is a calorie? A unit of energy that is used to show how nutritious certain foods are The amount of energy in the form of heat that it takes to raise the temperature of 1 gram of water 1 degree Celsius A vital nutrient that all animals require for survival The speciüc heat capacity of water is _____. (g x °C)/1 cal °C/(g x 1 cal) 1 cal/(g x °C) g/(1 cal x °C) A bomb calorimeter is used to measure _____ in reactions that occur in a constant volume. energy changes known quantities of water dietary Calories nutrient absorption Monosaccharides are the smallest building blocks of sugars and have similar chemical compositions. Considering that simple sugars are a component of carbohydrates, what is the general chemical composition of monosaccharides? C m (H2O) n CO n(NH 2) n CH 3(CH 2)COOH NH 3(H 2O) n Fats have a high amount of stored energy because _____. once ingested, they quickly and easily dissolve in the body making them readily accessible the hydrocarbon chains have many bonds that take time to break down Fats are actually low in stored energy due to a lipid barrier that makes the breakdown of these molecules more difficult than other sources of energy The primary diûerence between each amino acid is _____. the side chain (functional group) of the alpha carbon the carboxyl group of the beta carbon polar amino acids contain nitrogen, while non-polar amino acids do not polar amino acids are able to form inter-protein disulüde bonds, while non-polar amino acids cannot The primary use of ingested proteins in the body is to _____. be broken down into amino acids that are used to build proteins and nucleic acids within the body be broken down to release energy and the unused components are recycled to build new proteins within the body interact with signaling molecules to trigger the building of muscle übers be converted to starches or sugars, which are more readily accessible forms of energy The _____ must be collected in order to determine the caloric content of food using a bomb calorimeter. change in water weight the rate at which food burns change in water temperature change in volume of water lost A scientist would compare data collected with a bomb calorimeter to accepted values of caloric content in a speciüc food by _____. describing the values listed on a nutrition label calculating the percent diûerence between the data collected and data on a nutrition label recording detailed observations on the intensity and amount of ýame produced When using Atwater factors to determine the amount of calories from carbohydrates, it is necessary to subtract the über content, per unit of carbohydrate because _____. über cannot be broken down in the body, so it is not used for energy über is loosely bound to carbohydrate molecules, and are cleaved immediately after ingestion über should not be subtracted from carbohydrates because the binding of these molecules is what allow them to be an accessible form of energy über and carbohydrates are not related Extension Questions Explain how the following experimental errors aûect the ünal calculation of the kilocalories per gram for a food item. Be speciüc as to whether the ünal value will be higher or lower than if the error had not been made. a. The student misread the scale and recorded 110.3 g for the ünal mass of the soda can plus water instead of 101.3 g. b. Part of the unburned marshmallow fell oû before the ünal mass was determined. c. The food would not keep burning and had to be relit several times. d. The thermometer got stuck in the aluminum foil while the food was burning and the ünal temperature was made with the thermometer in the air above the water and not in the water. Experimental errors greatly aûect the ünal calculation of the kilocalories per gram for a food item. a) If the student recorded a inaccurately high mass, it would result in a higher value of energy released and value of kcal/g. b) If part of the unburned marshmallow fell oû before the ünal mass was determined, it would appear that the ünal mass is too low. From there, the kcal/g would be much lower. c) If the food would not keep burning and had to be relit several times then this would lead to the decrease in the mass of the food since it would not all be burning. As that would decrease, the kcal/g would increase. d) If the thermometer for stuck, it would lead to a decrease in the ünal temperature. The kcal/g would also decrease.