'Determination of % Composition of Pennies Using Redox and Double Displacement (Precipitation) Reactions Essay\r'

'Introduction:\r\nOxidation involves the gain of electrons of hydrogen or the loss of oxygen or reducing in oxidation state. If coat completely reacts with HCL, then(prenominal) the theoretical yield of grunter should be identical to the actual yield.\r\nPurpose:\r\nIn this lab, we volition gear up the pct composition of a modern ( dapple-1982) cent by using a strong pungent to react and dissolve the zinc core, leaving lonesome(prenominal) the grunter coating. Once only slob remains, we will compare its volume to the entire mass of the cent to bump how much of a cent is copper and how much is zinc. 1. Obtain one 50.0 mL beaker, and check off the beaker with your NAME and HOUR.\r\n2. Obtain a cent date 1982 or later. Wash the centime with soap and pee to get it clean.\r\n3. Using a triangular accommodate to make FOUR oppositely-placed sm completely grooves into the edge of the penny (the marks with be some 90 degrees apart. The grooves mustiness be deep enough so that the zinc is exposed, but not so deep that the penny’s mass is greatly affected.\r\n4. Clean the extend and bottom surface of the penny with steel fleece until it’s shiny. Rinse the penny in dimethyl ketone and dry it on paper towel.\r\n5. encounter the mass of the penny on the balance, and record the mass in the table on the bottom of the page. Removed the penny from the balance using tweezers and place it in its beaker.\r\n6. eon wearing gloves, carefully pour 50 mL 3M HCl into the beaker.\r\n7. Place your labeled beaker under the fume tinder to react. Observe the effect the acid has on the copper outside of the penny.\r\nQuestions to answer to help guide the maturation of cognitive processs for the determination of the percent copper and zinc in pennies through titration and gravimetric techniques:\r\n1. What is the weight of a post 1982 penny?\r\n2.5 grams\r\n2. What is the percent copper and zinc in a post 1982 penny?\r\n97.5% zinc, 2.5% copper\r\n3. H ow legion(predicate) grams of copper and zinc are in a post 1982 penny?\r\n97.5 grams zinc, 2.5 grams copper\r\n4. How umteen moles of copper and zinc are in post 1982 pennies?\r\n5. publish a balanced reaction of zinc with HCl.\r\nZn(s) + 2HCl(aq) â€> ZnCl2(aq) + H2(g).\r\n6. How many moles of HCl are needed to react completely with completely of the zinc in a post 1982 penny?\r\n2.5\r\n7. In a procedure developed to tally the percent zinc in post 1982 pennies, 50 ml of an HCl solving was used to react (dissolve) every(prenominal) of the zinc in the penny. To ensure complete reaction, the outcome contains twice as many moles of HCl that is actually needed. What niggardliness of HCl should be used?\r\nIn the scenario described in occupation 7, what is the amount (in moles) of\r\nexcess (unreacted) HCl in dissolvent?\r\n9. How many moles of NaOH would be needed to completely react with all of the excess HCl determined in job 8?\r\n10. As described in problem 7, a pro cedure was developed to determine the percent zinc in post 1982 pennies. In that procedure 50 ml of an HCl was used to react (dissolve) all of the zinc in the penny. To ensure complete reaction, the solution contains twice as many moles of HCl that is actually needed. To determine the percent zinc in the penny, the excess (unreacted) HCl was titrated with NaOH. Determine the concentration of NaOH needed if you want to use approximately 25 mL of NaOH to titrate the excess HCl.\r\n11. frame the balanced chemical reaction of zinc with HCl (same as problem 5). Is the product of this reaction soluble in aqueous solution?\r\n12. Write the balanced chemical reaction of the product of the reaction described preceding(prenominal) (problem 11) with NaOH. Is the product of this reaction soluble in aqueous solution?\r\n'