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UIUC CHEM 203 - Copper Iron pre Lab - 2

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Copper/Iron Stoichiometry LabIntroduction The Issue of pollutants in water is becoming more and more of a problem as industry keeps contaminating the ever-depleting freshwater supplies. A solution to contain these contaminants has been researched and can be performed by the use of reduction by iron1. There is much research and work being done to reduce these pollutants such as bromine or dinitroluenes2 to their elemental state, which is much lessharmful. The use of zero valent iron is essential to this success of reducing the Bromine from the water as stated by the department of civil engineering of the university of Hong Kong3. In this lab that, our goal is to reduce copper (II) sulfate with iron powder causing one of the two following reactions CuSO4(aq) + Fe(s)  Cu(s) + FeSO4(aq)3CuSO4(aq) + 2Fe(s)  3Cu(s) + Fe2(SO4)(aq)We will be performing a limiting reagent experiment to determine the formula for this copper. In the end of the experiment we will be able to determine which reaction was performed. If there is more moles of CuSO4 produced, than Iron was the limiting reagent and for the second reaction if the Cu produces to most moles than CuSO4 is the limiting reagent. One of the goals of this experiment is to find the limiting reagent by an experiment so by finding this we will also find the correct equation used. To perform this we will need to use a vacuum filtration method to separate the solution from product4.Materials and MethodsThe First step of this lab is to construct the vacuum filtration system. This is performed by using a glass crucible that is very clean. The crucible should be cleaned with a Kimwipe and always handled with gloves on and never with bare hands. Next weigh the crucible in the analytical balance and record the weight up to one tenth of a milligram and keep large metal objects and electrostatically charged items away from the balance. Next set up a vacuum filtration system. Refer to Figure 2-1 in the lab manual if there is uncertainty in the following description. There will be two 250 mL Erlenmeyer flasks connected by a hose adapter in one flask and a vacuum hose connecting to the other flask. Another hose will be connected to the flask with the adapter and connected tothe vacuum. The Flask with the adapter will be the trap and vacuum control and will havea clamp around it. The other flask will be the filter flask. It has a sintered glass crucible on top of it. Once again, if confused look to the figure 2-1 in the lab manual4. To prepare the reactants place 7.000g of CuSO4 in a clean 150mL beaker. Do this by weighing by difference. To do this, add the CuSO4 to a weighing bottle until there is a little more than needed (7.000g). Next place the beaker on the analytical balance. Then 2add small amounts of the solid into the beaker until the analytical balance reads 7.000g. Next using a graduated cylinder, add 50-70 mL of DI water to the beaker with the CuSO4.Next, weigh 2.000g of Fe by using the same technique used to weigh the CuSO4 and place it in a beaker. In order to carry out the reaction, first heat the CuSO4 solution and stir with a stirring rod. Do not let it boil. Transfer it to a beaker hood and then add the 2.000g of ironpowder. Do not keep this on the hot plate when adding the iron. Try not to inhale the fumes when performing this step. Rinse the beaker containing the Fe after this step and allow the beaker containing the solution to cool. In order to collect the Cu product use the vacuum filter created earlier, but first let DI water pass through to ensue the vacuum works. Be careful to make sure no product spills when transferring. Wash the solid over the vacuum with DI water. Measure the wash volume with a graduated cylinder. Next wash the solid using acetone in 15 mL increments, and then let the solid dry over the vacuum for 10 minutes. After it is dry remove the crucible being careful not to touch it with bare hands then place the solid on the analytical balance used in the beginning. Finally use the filtration system adding. HCl to remove copper collected. Then place waste in the carboy.Questions to Consider1. An error that would yield greater than 100% is that the copper was not left on the vacuum long enough causing excess water to be included in the final weight. A possible source of error that would yield something less than 100% is that some solution could be left in the beakers when transferring which would cause there to be not enough product to yield 100% in the end. 2. The limiting reagent is the reactant that first runs out of moles in a chemical reaction. 3. For the first reaction, 7.000g of CuSO4 which is .0439 moles is combined with2.000g of Fe which is .0385 moles. Therefore the Fe is the Limiting reagent, and it will produce 2.276g of Cu. For the second reaction the same amount of moles are used but because of themole to mole ratio the CuSO4 will be the limiting reagent. Therefore producing 2.787g of Cu. 3CuSO4(aq) + Fe(s)  Cu(s) + FeSO4(aq)3CuSO4(aq) + 2Fe(s)  3Cu(s) + Fe2(SO4)(aq)4. If Fe was the limiting reagent, there would be excess CuSO4 which wouldcause the ions of copper to be mixed with the pure copper, thus creating not a pure copper solution. 5. If the color stays blue, the iron is the limiting reagent because there is an excess of CuSO4 which is blue, and if there are still CuSO4 ions in the solution it will stay blue. If the CuSO4 is the limiting reagent, the iron ions will be in excess and there will be no excess ions that are blue.6. This should be added under the hood because it produces sulfur gas that is harmful.7. If the sample is left on for less than the amount of time needed the water will not be fully gone from the sample and the mass will be too high. If it is let on too long, the Cu will oxidize and the weight will be too high.8.Ba(NO3)2 + Na2SO4  BaSO4 + 2NaNO3 We are presented with 4.678 mol of Barium Nitrate, and 2.3777 mol of sodium sulfate. The sodium sulfate will be the limiting reagent because of the mole to mole ratio. In the end the molar mass of the solid, barium nitrate, is 233.39g/mol. The final mass of the solid is 554.931gReferencesButler, R.; Godley, A.; Lytton, L.; Cartmell, E.; bromate Enviornmental Contamination: Review of Impact and Possible Treatment. Critical Reviews in Science and Technology. 2005. 35.3Patapas, J.; Al-Ansari, MM.; Taylor, KE.; Bewtra JK.; Biswas, N.;. Removal of Dinitrotoluenes from water


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