Exercise 1: Determining the Caloric Content of Three Foods
Abstract:
In the beginning, I collected all the equipment that was required. After that, I emptied the balance and set it on zero and then, mass of the empty beaker was measured. Then, I added 50ml water into the empty beaker and checked the mass on the balance again. Afterwards, I take a foil paper and placed it at the bottom of the burner stand, and then I put the beaker containing the water on the stand for beaker. The initial temperature of the water was measured firstly, and then, I took a marshmallow and measured its weight with and without the fork to determine the weight of both. After all this, I lit the fire with the help of a lighter and after it started burning, I carefully placed it under the beaker present on the beaker stand. In addition, I started stirring the water with the help of a thermometer. After the lighted stopped burning, I measured the temperature again to get the final temperature. In this regard, I calculated the change in temperature that was determined by subtracting the final temperature from the initial one. After that, the weight of the fork as well as of the marshmallow was measured in order to know the final mass. I also got the change in temperature of the fork and marshmallow by subtracting the final reading from the initial mass. In this way, I repeated the same steps for cashew and chip as well and ensured that the beaker is clean and dry before starting the experiment. I have obtained the heat energy gained during the experiment by multiplying the change in temperature by the mass of water and 4.184 J/g°C. The heat energy per mass unit was also measured by dividing the heat energy gained by the mass of burnt food. In order to get the calories of the sample, I divided J/g by 4.184, which was later on divide by 1000 to know my calorie.
Observations:
Marshmallow:
I have observed that the marshmallows were very good as well as quick at catching the fire. After it was completely burnt, the flame lit for just one more minute and then stopped. I have not seen a lot of smoke coming out of the marshmallow, and finally, I noticed that the weight of marshmallow was much lighter after getting burnt as compared to the initial weight.
Cashew:
I noticed that cashew was hard to burn, but when it caught fire, it kept on burning longer than the other two samples. The flame while burning it was low and I saw some liquid coming out of cashew upon burning it. A small amount of black smoke was coming out of it after being burnt.
Chip:
I have selected a barbeque chip as a sample, and it caught fire easily than the other two samples. It got fire as soon as it was placed on the flame. I saw a bigger flame this time than the other two samples. It burnt so fast and so well and a lot of smoke was coming out of it, The color of smoke was black and the beaker also become black due to that smoke. Afterwards, while taking the measurements, I witnessed that the chip was lighter than it was before burning.
Data Table 1. Determining the Mass of the Water (g).
Data Table 2. Caloric Calculations.
Questions:
Compare the calorimeter that you built to a bomb calorimeter. How are they similar? How are they different?
It has been witnessed that the bomb calorimeter is dissimilar from the one I have built because mine is completely protected and insulated, and it can help in getting more accurate reading about the changing temperatures. The heat that came out of the burning sample may have impacted because it was also not enclosed as it used to be in a bomb calorimeter. The similarity among both of the devices is that they determine and calculate the same things, but the main difference is that one of them measures more accurately. Further, both of the devices burn the samples used and use the water and the change in temperature to determine the quantity of energy that came out during the experiment.
B. 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 differently if you had unlimited expenses for materials?
I do not think this calorimeter was better than the bomb calorimeter. The calorimeter we built is a pretty good way to measure the energy released but, not the best way. I think experimental error occurs because our calorimeter is not enclosed like a bomb calorimeter. Since it is not enclosed we do not get an accurate temperature change especially since some of the heat can be lost depending on the place that we perform our experiment. I think another experimental error can come into play when we are measuring the final mass or our calculations. If I had unlimited expenses I think I would find a way to insulate the equipment and make some sort of machine that would calculate the measurements for me with precision. It would also get the temperature change and weight at the same time. I noticed in the experiment that the temperature might be off because it took me a few seconds to put the sample down and accurately read the temperature. In the same way, it is possible that the mass of the sample was wrong because I may have lost some mass placing it down on the scale.
C. Based on how each food burned, which food would be the best to use for a fuel that has a steady flame 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?
Based on my observations, I think the peanut would be the best fuel supply once it was lit. I think this because the flame lasted longer and burned at a steady pace. It also did not give off a whole lot of smoke. Nuts are composed of carbohydrates and proteins. Not all carbohydrates are bad for you. Carbs are essential in our diet but, it is best to choose naturally occurring carbs. The body uses the carbs so that the proteins do not have to be used up so quickly in our body. It also gets stored in the body in case there is no ready available supply of glucose; for example when you are exercising.
D. Although protein was part of the composition of the foods in this experiment, it was not the main macromolecule component of the nut or the marshmallow. Why do you think this type of food may have been left out, based on what you learned about the way the fuel is “burned” in the body?
I think protein was left out because it probably would take longer to burn than the carbs and there might not be as much of a change in the mass as the peanut and marshmallow. If there wasn’t much of a change we might not grasp the concept as well as we did with the carbs that had a noticeable change.
E. Using your data, which food had the least amount of Calories per gram? Based on what you learned about the structure of each macromolecule, why is this true?
The cashew had the least Calories per gram. I think this is true because they are healthier for you. They still contain carbohydrates but, they contain the good ones. It also had the least amount of fat per gram unlike the marshmallow and chip.
F. 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?
When I determined the Atwater factors, I did get almost the same amounts of each macromolecule in the food. For the marshmallows I was off by .5, cashews by 6, and by 4 for the chip. I think this could have happened due to rounding or calculation errors. Or it could be that the exact amount is just estimated on the packages. I think my calculations might have been off as well because I was trying to find the calculations for just one instead of the serving amount which was 15 chip, 4 marshmallows, or 15 cashews. When I tried to determine the Atwater for the estimates the way they appear on the packaging I came even closer to the calories on the package but still not exact. I also think this could have occurred because of rounding error or because this was just estimated.
