How does the chemical composition and structure of a substance determine its properties with regard to its use, capacity for reuse, and capacity for recycling? Chemical composition is the way that a substance is made up. For example, salt is NaCl or sodium chloride. The Structure of a substance refers to the way in which the molecules of a substance are arranged and bonded. The chemical composition and structure of a substance determine its properties like if it’s magnetic or flexible or prone to corrosion or its solubility. These properties help manufacturers determine what a substance is good for. For example, if a substance is conductive it could be used to make electrical wire or if it’s not conducive it could be used as insulation. Materials, where the atom chains are longer, can be recycled for longer. Sum substances atomic chains/bonds don’t break down which makes them infinitely recyclable like aluminum.
How do the choices we make as consumers (purchasing, use, reuse, recycling, and discarding of materials) impact our local community and environment, and the global community and Environment? People don’t realize how much waste we actually produce. In the year 2017 as a country, we produced 267.8 million tons of solid waste. When you chose to buy packaged goods that packaging has to end up somewhere and what we are lying to ourselves about is that it won’t mostly end up in the landfill. Even things we don’t realize aren’t recyclable, like thin plastics ex. strawberry containers. When our recycling goes to the recycling center, the items that are actually recyclable have to be picked out of the trash. A lot of what goes to the recycling center actually ends up as trash. When people contaminate the recycling stream the process of separating and processing the recycling becomes more expensive therefore increasing the cost of recycling overall for the individual.
What else did you learn through this project? I learned a ton during this project. To start off, just basic chemistry like how to read and interpret the periodic table and periodic trends like how atomic mass increases and how atoms gain and lose electrons. I also learned a lot about recycling. I learned that some things that say they are recyclable aren’t actually, like strawberry containers. I learned that when substances that decompose do so abiotically they produce methane gas that is actually worse for the environment than plastic in landfills. During this project, I was exposed to chem labs which was a very cool experience. I learned about spectroscopy during labs and chemical formulas and lab safety.
Process/Procedure: Our first step was to measure the weight of the container that would hold our mixture. We weighed it in order to avoid any confusion around the weight of the mixture itself(as a precaution). Then we zeroed out the scale and measured 9.7g of the non-challenge mixture. Then we weighed a sample plate in preparation for the removed iron filings from the mixture. To remove the iron fillings we covered a magnetic stirring strip in plastic wrap so we could remove the iron fillings from the mixture using the magnet and also be able to remove them from the magnet once separated from the mixture. Then we measured the separated iron filings and subtracted the weight of the petri dish to determine the weight of the fillings. We should have zeroed the scale out to the right of the petri dish but we didn't think about it. Our next step was to ‘separate the peppercorns from the mixture. To do this, we again measured the weight of a petri dish to put the separated peppercorns in. Then we used forceps to grab the individual popcorns. We were able to use forceps because of the peppercorns' macroscopic size. We proceeded to weigh the peppercorns. After that, we were left with a mixture of potassium aluminum sulfate (alum) and silicon dioxide (sand). We put the remaining mixture into a beaker with 30ml of room temperature water. The effect of this was that the alum dissolved. Then we poured the mixture through filter paper, to sift out the sand, into a second beaker. We then dehydrated the damp sand still on the filter paper in the oven order to remove any non-sand weight from the specimen (to stay precise as possible). We weighed the sand on a petri dish. To get the alum back out of the water we dehydrated it on a hot plate and on the hot plate until it was back to a sticky powder form. Then we moved the leftover powder into a sealed container. We measured the weight of a third petri dish and zeroed out the scale so we could measure the dehydrated alum weight on our petri dish. Then we used our calculations of how much each component weighed and divided them by the weight of the total mixture (9.7) to find out what the percent composition of the mixture was made up of what component.
Conclusion: The task of this lab was to determine the percent composition of the mixture. We did this by separating the individual substances weighing them and dividing the individual substance weights by that of the total mixture weight. Our methods were definitely not good enough to be used in any professional setting but, within the context of this lab were sufficient. By this, I made that what we did was generally correct in theory (we did achieve the goal of separating all the materials of the mixture) however, we did end up losing 7.685% in the process. Our method was not fast enough to get us 100% completed within the allotted time. We could definitely have gone faster. I do believe that the errors in both timing and precision, were due to our inexperience. It was not particularly challenging though which was to our benefit. As stated above we lost 7.685% or .07685g during our experiment, specifically when transferring substances from container to container. When we were pouring our mixture of alum dissolved in water and sand through the filter paper, there was sand residue left in the original container so, we lost some mass in the sand there. Also, after we had re-dehydrated our alum it was stuck to the bottom of the container. I believe that we lost some mass in alum during the process of removing it from the dehydrating container. It is reasonable that the combination of these two loss points makes up the missing 7.685% mass of the total original mixture. Our results were quite different from the expected results I believe that part of the reason that our results differed was not even error but because the percent composition was actually indeed different. For example, our mixture had many peppercorns, 29.07% to be precise and Chris’s mixture had only a single peppercorn in it. The individual materials within the mixture were apparently not evenly distributed. This would automatically skew out results. However, I could be wrong and the error was our fault. The predictor percent composition of iron was 22.5% our results were 12.37%, this is a 10.13% loss. he predictor percent composition of the sand was 39.4% our results were 29.175%, this is a 10.226% loss. The predictor percent composition of the alum was 26.8% our results were 21.07%, this is a 5.73% loss. The predictor percent composition of the peppercorn was 11.3% our results were 29.07% this is a 17.77% gain. If you have too much peppercorn, because it is unequally distributed then every other percent must be too little.Two reasons that we could have been incorrect could have been that our masses were different due to loss while transferring substances from container to container or we had an error when we were measuring mass. Given the chance to reduce this experiment I would improve our methods by being way more careful about transfers. I believe that our 7.685% loss in mass was due to discrepancies during container transfers where the popout be to dehydrate a substance or put it in a weighing container. Secondly, I would remember to use distilled water to dissolve out alum instead of using tap water. Questions for Further Thought:
No, because the different components may not be evenly distributed throughout the mixture. For example, our mixture had many peppercorns, 29.07% to be precise and Chris’s mixture had only a single peppercorn in it. However, should the mixture be evenly distributed, then yes, the percent composition should be extremely similar if not exactly the same.
Single stream recycling is a system of recycling where all recyclable materials (and nonrecyclable materials that have to be sorted out as we are learning) get put into the same bin to be picked up by the recycling company.
According to the video, “Tour of London's Recycling Center”, three ways to mechanically sort recycling are using UV light for plastics, magnets for iron cans, and electrifying aluminum to create a magnetic field. There is a machine that uses UV light to see what types of plastics are going through it. Once it knows what type of plastic it is it signals an air stream to blow the plastics in the directions they are being sorted. There is a magnetic conveyor belt that removes the iron products, cans and whatnot from the mixture. And a different type of magnetic field, one created by electrical currents is used to remove aluminum.
The error is that the filter paper is wet when it was weighed adding inaccurate mass to the measurements. To correct it the student should have dehydrated it first.
The error was not wrapping the magnet in plastic wrap first. To correct it wrap it in plastic wrap before removing the ion filings from the mixture.
The error was not weighing the glass before putting in the substance. This would make it impossible to accurately weigh the substance. To correct it the student should have weighed the glass. But since they already messed up there best bet is to be really careful transferring to a new pre-weighed container.
The error was letting the water get to a point where it was boiling hard enough to spill out. To correct this they could have used a larger container or put a lid on the one they were using.
The error is using tap water because tap water has chemicals and other substances in it that will affect the results of the test. The solution would be to use distilled water.