Drew RasmussenPartner: JayInstructor: Katri TruhlerChemistry 112 LabMarch 24, 2011Colorimetric Determination of Copper in a PennyA.Research Question:a.What is the percentage of copper in the assigned penny?B.Theoretical Approach:a.From Beer’s Law we know that concentration and absorbance are directly related,thus as concentration increases absorbance will increase, and as concentrationdecreases, so will absorbance.With CuSO4* 5H2O a standard curve can becreated by generating different stock solutions, varying only by concentration.Bygraphing the Absorbance vs. Concentration of our 6 standard solutions we shouldget a relatively linear line (and an equation for the line) that can be used todetermine the percentage of copper in our penny by simple calculations, andplugging in the absorbance reading of our penny at a maximum wavelength.C.Observations and Results:a.The penny used was a 1986 penny, that was relatively clean for its age. It wasn’ttoo tarnished, and it was in good shape. It weighed 2.540g (+ or – 0.001g).b.Our group was assigned a stock solution of 0.100g of Copper per 250 mL.Through calculations and knowing the molecular weight of CuSO4* 5H2O, wecalculated that 0.392g of the solid would have to be added to produce our