CHE 5503 -Instrumental Analysis Midterm IIProf. Terry A. RingOpen Book & Open NotesName:____________________________SID#:_____________________________Score1)__________2)__________3)__________Total __________1Problem 1 (30 points)In the AA analysis of Gatorade, the following data was obtained.Solution Concentration (mg K/L) Absorbance (dimensionless)Blank 0±0.02 0±0.001Std #1 1.01±0.02 0.0038±0.0009Std #2 2.00±0.02 0.011±0.001Std #3 2.99±0.02 0.018±0.001Gatorade after HCl Digestion and Dilution- 0.013±0.004This data has the calibration curve given byA=0.0056 C(mg/L).a) Determine the concentration of potassium in the Gatorade.b) Determine the standard deviation of the concentration of potassium in the Gatorade.2Problem 2 (40 points)Attached is a spectrum for natural gas taken with the FTIR spectrometer using the gas sample cell. In addition the spectra of a sample of 10.1 ppm methane and 10.0 ppm CO2 in the same sample cell has been obtained. Using the 3010 cm-1 peak for methane and the 2360 cm-1 peak for CO2, determine the concentration ratio of CO2 in the natural gas to methane (CH4) in the natural gas.Figure 1 FTIR spectrum of Natural gas3Wave Number (cm-1)Figure 2 FTIR spectrum of 10.1 ppm methaneFigure 3 FTIR spectrum of 10.0 ppm CO245Problem 3 (30 Points)The following results were obtained for the Absorbance of an unknown in the UV-Vis spectrometer (Spectronic 21). You suspect that the 4th trial is faulty. Use Chauvenets criterion to determine if it and any other values can be eliminated from the mean and standard deviation of this absorbance data.Chauvenet’s CriterionDataTrial Absorbance1 0.0192 0.0173 0.0204 0.0295 0.0186
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