 # 1 a sophisticated uvvisiblenear ir instrument has a

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1. A sophisticated uv/visible/near IR instrument has a wavelength range of 185 to 3000 nm.What are its wave number and frequency ranges?
2. A typical simple infrared spectrophotometer covers a wavelength range from 3 to 15 μm.Express its rangea) in wave numbersb) in hertz(a)ν =13µm×104cm/µm= 3.33 × 103cm–1to115×104cm= 6.67 × 102cm–1(b) ν = 3.00×1010cm s–1× 3.333×103cm–1= 1.00 × 1014Hz to3.00×1010× 6.67×102= 2.00×1013HzQuestions:1. Why is a solution of Cu(NH3)42+blue?
Lesson 3BEER-LAMBERT’S LAWActivity 1
Practice exercises1. Express the following absorbances in terms of percent transmittance:
B)B) 0.379
C)C) 0.485
2. Convert the following accompanying transmittance data to absorbances:A) 25.5%
B) 32.8%
3. A solution containing 4.48 ppm KMnO4has a transmittance of 0.309 in a 1.00=cm cell at 520nm. Calculate the molar absorptivity of KMNO4.
Lesson 4HOW THE UV-VIS SPECTROPHOTOMETER OPERATESActivity 1
A compound X is to be determined by UV/Visible spectrophotometry. A calibration curve isconstructed from standard solutions of X with the following results: 0.50ppm, A- 0.24; 1.5ppm.,A=0.36; 2.5ppm, A=0.44; 3.5ppm, A=0.59; 4.5ppm, A=0.70. Find the slope and intercept of thecalibration curve (recall lesson in physics or geometry), the standard error in y, theconcentration of the solution of unknown X concentration and the standard deviation in theconcentration of X. Construct a plot of the calibration curve and determine the unknownconcentration by hand from the plot.123450.000.100.200.300.400.500.600.700.80Concentration in ppmAbsorbanceConc. In ppmMeasured A0.50.241.50.362.50.443.50.594.50.70Unknown0.50Regression EquationSlope0.115Intercept0.1785Concentration of unknown2.7957Error AnalysisStandard error in y0.017029N5S xx10Y bar (avg. absorbance)0.4660M1Std. deviation in c0.1628
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Term
Fall
Professor
Feliza
Tags
Cathode
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