Raw DataExplanation:IDExplanation:CHEM 211 LaboratoryAbsorption SpectroscopyData Analysis SupplementReference: General Chemistry Laboratory Experiments, Suzanne W Slayden, 1999, 3rd edition, Pages 37-48Data: After you have recorded all the wavelengths and absorbances, enter your own data into the appropriate Web-based data entry form, using a computer in the lab. In your measurements and calculations, remember to pay attention to uncertainties and significant figures.Results: Outside of class, retrieve your data in spreadsheet form (along with that of the entire class) from:http://chem.gmu.edu/results/. Then use Excel to calculate the concentrations of the two standard solutions.Your lab report should include the following in addition to the pages from your lab notebook:- An Excel sheet “Raw Data” showing the raw data for the entire class (as downloaded). A typical example of the raw data sheet is shown below:Raw Data Explanation:o Lambda_max: wavelength of maximum absorptiono Conc_stock: concentration of stock solutiono Vi_A: volume of stock solution in standard solution 2o Vf_A: diluted volume of solution 2o Vi_B: volume of stock solution in standard solution 3o Vf_B: diluted volume of solution 3o Abs_stock: absorbance of stock solutiono Abs_A: absorbance of standard solution 2o Abs_B: absorbance of standard solution 3o Abs_water: absorbance of watero Abs_unknown: absorbance of unknown solution- A 2nd Excel worksheet “Results” showing the calculated results for each student in the class – each in a separate row. Make sure to show an example calculation for each column. This can be done by copying the equation from the formula bar to a blank cell below the elements in the table.An apostrophe in front of it makes it text instead of an equation. Each table should be formatted as in previous classes with lines separating the table headings from the contents. A line below thecontents should also be drawn. A typical example of the results sheet is shown below:1 A B C D E F G H I J K L M1ID MetalLambda_maxConc_stock Vi_A Vf_A Vi_B Vf_B Abs_stock Abs_A Abs_B Abs_water Abs_unknownnm M ml ml ml ml2 1 Nickel 660 0.200 3.18 9.92 6.98 10.00 0.31 0.09 0.21 0.31 0.123 2 Cobalt 510 0.200 3.10 9.98 7.10 10.25 1.07 0.30 0.73 0.00 0.50ResultsA B C D E F G H I J K L1ID[1] [2] [3] [4] Abs_1 Abs_2 Abs_3 Abs_4 Slope Intercept [Unk]M M M M M2 1 0.000 0.060 0.140 0.200 0.31 0.09 0.21 0.31 2.25 0.0360 0.1133 2 0.000 0.060 0.467 0.200 0.00 0.30 0.73 1.07 0.56 0.0990 0.180Explanation:o [1]: concentration of watero [2]: concentration of standard solution 2o [3]: concentration of standard solution 3o [4]: concentration of stock solutiono Abs_x: absorbance of solution x (x = 1-4)o Slope: slope of the absorbance on y- axis vs. concentration on x- axiso Intercept: intercept of the absorbance on y- axis vs. concentration on x- axiso [Unk]: experimentally determined concentration of unknown solution. The equation that relates absorbance to concentration is Abs_unknown = slope * [Unk] + intercept. Use the straight line slope, intercept and the unknown's absorbance to calculate this value.- A 3rd Excel sheet “Spectrum” showing an XY (Scatter) chart between the wavelengths on x-axis and absorbance on y-axis of the absorbing species. Use the appropriate line option of the graph toplot a smooth line joining all points. Check whether the -max is the same as you have determined in lab. - A 4th Excel chart “Calibration Curve” showing an XY (Scatter) chart between the concentration on x-axis and absorbance on y-axis for each standard solution. Use the trend-line option to obtain the best straight line and the equation. Refer to http://chem.gmu.edu/Graphing%20with%20Excel.docPrinting Tables:- Large tables should be printed in the landscape mode and sometimes it might be necessary to go to “page setup” and select “Fit to 1 page” to make the page fit on one page. - Include column and row headings on the printout so that the instructor can more easily understand equations used. This can be done by going to File → Page Setup → Sheet tab → Select “Row and Column Headings”.Discussion: In your discussion section address the following questions:- Why do you need to calibrate the instrument every time you change the wavelength? What precautions do you need to take while calibrating the instrument?- What could be the reasons for the difference between the experimentally determined concentration and the true concentration for your unknown?- Why is it necessary to measure the absorbance at -max? - Can you visually estimate the concentration from the relative color intensity? Explain.- What is the -max from the Spectrum graph and is it the same as what you used for the absorbance measurements of solutions?- According to Beer’s Law, absorbance is proportional to concentration. Does your calibration curve support