Steel Wool Experiment

Google Doc Access Directions: ●​ Please click on File in the upper left corner. ●​ If you are working on a Chromebook or Google Docs, choose the Make a copy option and save a copy of the document to your Google Drive. ●​ If not, choose the Download as an option and then the Microsoft Word (.docx) option to download an editable copy of the document to your computer. Module Seven Lesson One Activity​ Steel Wool Experiment In this activity, you will watch a video of steel wool burning; this video can be found in your Module Seven Lesson One Activity instructions in Canvas. ​ ​ Answer the following questions. Notice that Parts 1, 2, and 3 are meant to be answered at different points in your viewing experience. Part 1 (Complete Before Viewing the Video): 1.​ Briefly explain the law of conservation of matter. The law of conservation of matter explains that matter cannot be created or destroyed, it can only be transformed. This means that in a chemical reaction, all reactants must be the same amount as the products. This is because in a closed system, matter will change but it will always stay the same amount as before the reaction. 2.​ Steel wool reacts with oxygen in this experiment. Hypothesize what will happen to the mass of the steel wool on the scale as the experiment progresses. I will hypothesize that the mass of the steel wool on the experiment will decrease. This is not because matter is destroyed, but because the steel wool will evaporate into the air. ​ Part 2 (Complete While Viewing the Video): 3.​ Record the beginning mass shown on the scale: 27.37 g 4.​ Now watch the video. What are your initial reactions and observations? As the steel wool burns, the mass decreases at first but then continuously increases. The mass started with 27.37 g and ended with 29.11 g. 5.​ Record the mass at each time stamp of the video in the chart below: Timestamp 0:10 0:15 0:20 0:25 0:30 0:35 0:40 0:45 0:50 Mass 27.38 g 27.28 g 27.28 g 27.26 g 27.25 g 27.30 g 27.59 g 27.92 g 28.17 g Timestamp 0:55 1:00 1:05 1:10 1:15 1:20 1:25 End Mass 28.44 g 28.62 g 28.82 g 28.93 g 29.00 g 29.06 g 29.10 g 29.11 g Part 3 (Complete After Viewing the Video): ​ 6.​ Do you notice any difference between the mass at the beginning of the video and the mass in the first 20 seconds of the steel wool burning? What could account for this difference? In the first 20 seconds, the mass of the steel wool decreases. This is most likely because of particles burning off and incorporating into the air. 7.​ Steel wool is made from fine pieces of iron which when burned reacts with oxygen in the following chemical equation. 4Fe + 3O2 → 2Fe2O3 Given your starting mass of iron from question #3, calculate how many grams of oxygen are needed to react completely with iron using stoichiometry. 27.37 g Fe 1 mol Fe 3 mol O2 32 g O2 55.845 g Fe 4 mol Fe 1 mol O2 (27.37x1x3x32)/(55.845x4x1)= 2627.52/223.38= 11.76 g O2 ANSWER: 11.76 grams of oxygen gas are needed to react completely with 27.37 g of iron. 8.​ Add your starting mass from #3 with your answer from #7, how does that compare to your ending mass? What could explain the difference? Starting mass=27.37 g Answer= 11.76 g 27.37 g+11.76 g=39.13 g Ending mass= 29.11 g Difference=10.02 g The 10.02 g difference between the calculated final mass and the actual ending mass is most likely explained by the fact that in the video, all of the steel wool did not burn. So, not every piece of steel wool got to react with oxygen and in the equation it is calculated for the steel wool to react completely with oxygen.