CO2 Powered Bottle Rocket Lab Report Chemistry Period 3. Crater School of BIS March 2 nd, 2016 Mallory Heard, Griffin Hokanson & Joshua Idiart

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1 CO2 Powered Bottle Rocket Lab Report Chemistry Period 3 Crater School of BIS March 2 nd, 206 Mallory Heard, Griffin Hokanson & Joshua Idiart

2 Introduction: The purpose of this lab was to design and create the most cost effective rocket that could go the highest. To do this, the molar ratios of the components involved in the chemical reaction were found, looked at, and optimized, using the limiting and excessive reagents. We were given the choice to use vinegar (HC2H3O2) or citric acid (C6H8O7) in the bottle to react with the baking soda (NaHCO3). When looking at the molar ratio in the chemical equation of each, we can see that when citric acid reacts with baking soda, more CO2 is produced than in a reaction with vinegar. Citric Acid: 3NaHCO3 (s) + C6H8O7 (aq) = 3CO2 (g) + 3H2O (l) + Na3C6H5O7 (aq) Vinegar: NaHCO3 (s) + HC2H3O2 (aq) = CO2 (g) + H2O (l) + NaC2H3O2 (aq) Three times more CO2 is produced than if we were to use vinegar. Carbon dioxide is the most important product in this lab because the more air produced in the reaction, the more pressure there is in the bottle, making it go higher! A one liter bottle was used because it was half the price of a two liter ($25,000), and with less volume, less reactants would need to be used. Three cardboard wings were placed at the bottom of the rocket to ensure stability in flight. The cardboard wings were all the same right triangle shape, that added up to be cm 2. The cardboard cost $2,000 per square centimeter, adding up to $89,000. A cork that cost $50,000 was put in the bottle to hold the substances inside, and to create pressure. A cone was placed on top of the rocket in effort to keep the bottle going straight into the air instead of going off to the side. The cone was made out of a manila file folder, and was donated. A tissue was also used to separate the acid from the baking soda to allow time to step back from the launch pad. The tissue and launch pad were also generously donated.

3 The rocket alone, without the fuel cost $,066,000. That left our group with $434,000 left over for baking soda and citric acid. That was split up precisely, and accurately, using dimensional analysis and some guessing and checking until 7.2 grams of baking soda ($72,000), and 3. grams of citric acid ($262,000) were used in the final launch. See Data Analysis for further explanation and problem solving behind those numbers. Equipment and Materials: Liter Aquafina Water Bottle Cardboard Cork Water Citric Acid (00%) Baking Soda Electrical Tape Scotch Tape Manila Folder Scissors Ruler Launch Pad Physics ipad App Kleenex Tissue Digital Scale Procedure: All materials were obtained and placed at the work table. A one liter bottle was emptied of its contents and placed to the side. A cone was formed out of a file folder to fit onto the bottom of the bottle and was taped on with electrical tape. Three right triangle fins were cut from a cardboard sheet with scissors. Each fin had dimensions of 9cm in height by 5.5cm in width. The fins were spaced evenly at the top of the bottle (bottom of the rocket), and were connected with electrical tape. A cork was found that would fit in the bottle opening tightly and would not slide easily out, or stay stuck when pressure was applied. The bottle was filled with 8 ounces of water and 3. ounces of citric acid. The amount of citric acid was measured on a digital scale on top of a piece of paper. The cork was put into the opening in the bottle and the rocket was shaken to disperse the citric acid in the water. The cork was taken off and screwed onto the launching pad. 7.2 grams of baking soda was massed on a digital scale on a piece of tissue paper and was

4 rolled up inside the tissue like a burrito. All materials were taken outside to the launching area. The rocket was carried upside down so its contents wouldn't leak out. The rolled tissue of baking soda was quickly placed inside the bottle and the cork attached to the launch pad was pushed into the rocket. The rocket and pad were flipped upside down and placed on the ground, as seen in Figure 2. A meter stick was held next to it and the launch was filmed through the physics ipad app. After the launch was complete, the video was reviewed, and the track of the rocket was plotted on the ipad, calculating the height of the launch. All materials were brought back inside, and the results were recorded. Data: Table - Varying Substance Amounts on Height of Rocket Trials (Practice Launch) 2 (Practice Launch) 3 (Final Launch) Mass of Moles of Mass of Moles of Height of NaHCO 3 NaHCO 3 C 6 H 8 O 7 C 6 H 8 O 7 Rocket 7.0 g mol 3.0 g mol 0.0 m 7.0 g mol 3.0 g mol. m 7.2 g mol 3. g mol 6.2 m Figure - Height of Rocket over Time (Final Launch)

5 Figure 2. Bottle Rocket on Launch Pad Data Analysis: Table 2- Costs of Rocket Liter Bottle () $25,000 Cork () $50,000 Fins (3) $89,000 Citric Acid (3. g) $262,000 Baking Soda (7.2 g) $72,000 Water (8 oz) Donated Tape Donated Nose Cone Donated Tissue Donated Total Cost: $, 499,000 The bottle ($25,000) and cork ($50,000) were the only components to the rocket that were made at a flat-rate. As for the fins, citric acid, and baking soda, some calculations had to be made. For the fins, the area of the right triangle was found using the formula: where b = base, and h = height of the triangle cm2 for one triangle was found. That was then multiplied by 3 (3 fins), which equaled cm 2. The cost of cardboard was $2,000/cm 2, so we did dimensional analysis to get the final answer of: cm2 $2,000 $, 2

6 The reactants were a little trickier to figure out. It was determined to use citric acid over vinegar because, using dimensional analysis, citric acid was much cheaper. When plugging in a random value of baking soda (NaHCO3), for both vinegar and citric acid, one can see how much each of the acids would cost for the same amount of base = 4 ml of vinegar, multiplied by $0,000 = $,40, = 7.62 g of citric acid, multiplied by $20,000/g = $52, From these calculations, it is obvious that vinegar is way too expensive to use for such a small amount of baking soda, but citric acid is very reasonable. Now, the exact amounts of reactants needed to be calculated, without any limiting or excessive reactants. Excessive reactants means ingredients, left over, and we don t want any leftover ingredients, because that is a waste of our limited budget. It was evident that there was $434,000 in the budget for the two reactants. The number that was calculated from the original guess of 0 g of baking soda seen above was actually close to budget, but too short, so 20 grams of baking soda were guess and checked next = 5.25 g of citric acid x $20,000/g = $305,000 x $200,000(baking soda) = $505,000 It turned out that 20 grams of baking soda was too much, and went over budget, so 7 grams was guessed next: = 2.96 g of citric acid x $20,000/g = $259,200 x $70,000(baking soda) = $429,200

7 That s so close! With only $5,000 off budget, we decided to go a step further and test 7. grams of baking soda finally. Below is the calculation for our final, and most accurate measurements of reactants so there are no limiting or excessive reactants. Also, attached behind this report is a hand-drawn blueprint of the rocket used in the lab = 3. g of citric acid x $20,000/g = $262,000 x $7,000(baking soda) = $433,000 Conclusion: The purpose of this lab was to construct the most cost effective bottle rocket to be able to fly the highest. To do this, limiting and excessive reactants had to be taken account of, because they had to be perfectly calculated so nothing was left over or in need, to maximize the budget. In this lab, the goal was achieved. The rocket was able to go at its maximum height of 6.2 meters while staying within the budget of $.5 million. Not only was it in budget, but it was only $,000 off! The rocket didn t just get built, then fly over 8 feet though. It went through two trial runs, which helped immensely by providing evidence of changes that needed to occur. Even after the third, final launch, there was still some improvements that could be made, but time, recourses, and ability unfortunately kept further trials from happening. In the first trial, 7 grams of baking soda was wrapped in a paper towel. When the launch occurred, and the rocket was flipped upside down on the launch pad, as seen in Figure 2, not much happened at first. The bottle rocket just sat on the launch pad for a minute or so, and a tester went to shake it to try to get the baking soda out of the paper towel. When the tester shook the bottle, the cork came out, and everything exploded on her. This happened because the paper towel was too thick of a catalyst for the baking soda, and wasn t permeable enough for it to go through. Also, the cork that was fitted onto the bottle s

8 opening wasn t tight enough, so when the tester lightly shook the bottle, it came out, spilling everything. It was decided that some necessary changes needed to occur, so the paper towel was switched to a tissue for the next round to create a thinner membrane for the baking soda to be held in. Also, a new cork was found that wasn t loose on the bottle s opening, but also not to tight so that it could be taken out without too much strain. On the second run, the changes were made from the first run, but still only 7 grams of baking soda, and 3 grams of citric acid were used. Also, the nose cone and fins were only taped on with Scotch tape. When the launch occurred, the cork was not screwed on straight to the launch pad, so the rocket went very skewed to the left, and didn t go high at all. It only went. meters. From this practice launch, it was decided that the measurements of the reactants needed to be much more exact. Also, the nose cone and fins were taped over again with electrical tape to increase stability, and to help the rocket fly straighter. To prepare for the final launch, exactly 7.2 grams of baking soda and 3. grams of citric acid were scaled, to be more accurate and precise. Also, the cork was made sure to be screwed on straight, to insure the rocket fly straight. Because of this precision, the rocket was able to fly 6.2 meters high, which was the second highest in the class! Even though the rocket was able to fly over 8 feet, some changes could be made that would make it even better for future experimentation. Since the rocket only costed $,499,000, in a more perfect world, it could have been more precise to use up that extra $,000. The digital scales we used in this lab only went to the tenth decimal place, so that limited our accuracy. If a more accurate scale could be used, one could possibly use for example grams of baking soda, and 3.46 grams of citric acid, to not only be more precise, but use up every last dollar. Also, the rocket didn t fly completely straight, it tilted somewhat to the left, making it not

9 go as high, so to counteract that tilt, a weight made of Play-Doh could ve been put on the bottom of the rocket to create more balance. Overall, this lab was an experiment of trial and error; limiting and excessive reagents; and creative problem solving. By finding problems and fixing them, the rocket was made slowly more accurate, making it fly higher and higher. Limiting and excessive reactants needed to be eliminated to be able to stay in budget, while finding the exact amount of fuel for the rocket. Lastly, creativity was key to be able to design and build the most cost effective, but at the same time, well-built bottle rocket.