Mass of aspirin used is .090 g the absorbance for the final solution was .304 nm Slope is 1708 and y-intercept is -0.03397what is the molarity of the final unknown solution and the molarity of the original solution made from aspirin in the 250.0 ml flask C) Preparation of Aspirin Sample for Analysis1) Grind 3 or 4 commercial aspirin tablets into a homogeneous powder using mortar and pestle.Weigh out 0.075 - 0.090 grams of aspirin onto a piece of weighing paper. Record the masscarefully. Note that it is crucial that you get as precise and as accurate a reading as you can onthis mass (Sig. Figs!).2) Transfer the ASA carefully avoiding spilling any to a clean, dry 125-mL Erlenmeyer flask.Add 10.0 mL of 1.0 M NaOH to the flask to begin your hydrolysis of ASA.3) Add a glass stirring rod to the solution and then heat it to boiling on hotplate at med-lowstirring the solution. Boil for at least five minutes to ensure complete hydrolysis.4) Cool solution until you can handle the flask and then transfer the solution Quantitatively to aclean 250-mL volumetric flask, which has been rinsed thoroughly with distilled water. It doesnot need to be dry inside. Rinse the Erlenmeyer flask twice with distilled water and transfer tothe 250-mL volumetric flask. Then fill the 250-mL volumetric flask to its calibration markwith distilled water. Put on a stopper (or parafilm) and shake the flask to thoroughly mix thesolution.Note: Your solution contains ASA but it is not purple yet because there is no iron to makethe purple complex. That will be added next.5 This means be careful and do anything you can to ensure that all of the solution ends up in the volumetric flask. Inparticular, rinse the Erlenmeyer thoroughly and add rinse solution to the flask.Colorimetric Analysis of Commercial AspirinPage 7 of 105) Your solution is still too concentrated in ASA to measure on your calibration curve you willneed to dilute it in this step. Pipette 3.00 mL of the solution you prepared into a clean 25-mLvolumetric flask that has been rinsed well with distilled water. Then dilute your sample to thecalibration mark with the acidic FeCl3 solution provided in the lab. Cap and shake to mix.This is the step where the purple color develops as your ASA molecules tie up with Fe³* ions.Note: If you do not get a purple color of if the purple color does not persist, check withyour instructor because something is wrong.D) Measurement of Unknown and Continuing Calibration Sample1) Fill a cuvette 3/4 full of the solution you made in the 25-mL volumetric flask. As beforecheck that your blank is within the 0.000 to 0.010 range. Place your unknow sample in theSpectroVis and measure its Absorbance at 530.3 nm.2) Record your Absorbance. You will use your Calibration Curve from part B to determine themolarity of your final sample in part E.3) Calibration Verification Step: To verify the accuracy of your calibration curve, we willrepeat the measurement of standard B. Your absorbance reading should be within 20% of thevalue from part B. Otherwise, you will need to repeat part B4) Clean up and discard your unknown and calibration solutions in the Inorganic Waste container. 1) Determine the Molarity of your Final Sample in part D from the Calibration Curve. You canuse the equation of the regression line (y = m x+ b) and solve for your unknown concentration(x) using your Absorbance reading (y). Mark your curve showing the Absorbance youmeasured and the molarity you calculate for this final sample on the graph you turn in.2) Calculate the molarity of the original aspirin solution you had before dilution from themolarity you got from the calibration for the final solution you had after doing the dilutionusing the dilution calculation:Minitial Vinitial = Mfinal V final3) Now that you know the Molarity of the solution you had in the 250.0 mL volumetric flask, usethe molarity to calculate the number of grams of ASA (C,H8O4) you must have had in thatflask.4) In Excel, highlight the Conc vs Absorbance data, click on insert and then select insert scatterchart (see screenshot below)Page 8 of 10iment # 10AutoSave eonColorimetric Analysis.alx- ExcelP SearchGarner, Mark GMHomePage LayoutDataReviewViewHelpAcrobatChart DesignFormatPCommentsInsert- - i-SymboksPivottable Recommended TablePivottablesIlustrationsAdd-TextWirytossinsChartsTblesChartsToursChart 1DH1 Concentration AbsorbanceFormat Trendline21.50E-030.215Beers Law PlotChart ElementsOptions3.00E-030.445Axes0.94.50E-030.627y-140.330oos6.00E-030.856R-0.99860.77 SlopeY-interceptO Error Bars81.40E+020.0095MovingAveragePeriod 2O LegendM Tendine10 Unknowne Name112.25E-030.3250.3tomaticLinear (Series1)120.213Custom140.1Forecast15Forwardperiods0.00 00 1.00E-0 2.00-0 3.00E-0 4.00-0 5.00-0 6.00-03 7.00-0317Concentraton (M)Backwardperiods18OSet Intercept19V Display Equation on chart21V Display 8squared value on chartSheett5) You will want to add a trend line (linear fit) to the chart, click on + trend line more optionsthen scroll down to select display trend line and R-squared value on the chart. Check that youhave a R-squared value (regression) of 0.995 or better. Then find the slope and y-intercept forthe data.6) We assume all the ASA present in the aspirin sample you weighed out is in this stock solution,so calculate % ASA in the aspirin.7) We can check the error in the % ASA found for your unknown by determining the amount ofASA in an aspirin tablet. Read the amount ofACETYLSALICYLIC_ACID on the aspirinbottle. Weigh an aspirin tablet. The % ASA = (mass of ASA / mass of aspirin tablet) x 100%.Find the error in your % ASA(1%ASA – Exp %ASA||-% Error =* 100%ASA

Given: Mass of aspirin used = 0.090 g The absorbance for the final solution was = 0.304 Slope is…

Mass of aspirin used is .090 g the absorbance for the final solution was .304 nm Slope is 1708 and y-intercept is -0.03397 what is the molarity of the final unknown solution and the molarity of the original solution made from aspirin in the 250.0 ml flask

Mass of aspirin used is .090 g the absorbance for the final solution was .304 nm Slope is 1708 and y-intercept is -0.03397 what is the molarity of the final unknown solution and the molarity of the original solution made from aspirin in the 250.0 ml flask

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter16: Applications Of Neutralization Titrations

Section: Chapter Questions

Problem 16.18QAP

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