Lab report

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timer Asked: Dec 3rd, 2018

Question Description

Environmental lab report needed ASAP plz .. I’m providing the procedure just follow what’s in th

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5. UV-Vis Spectroscopy 5.1 Introduction Objective Review basic analytical chemistry skills, including solution making, transferring and linear diluting. Understand the error involved and error propagation. Materials: Methylene Blue C16H18CIN3S, MW 319.85.Also called Swiss blue. One gram dissolves in about 1000 ml of water. Peak absorption at 369 nm (+) -CH₃ CH3CN CH3 -CH₃ 5.2 Create Calibration Curve from standard solutions Procedures: 1. Weigh 500mg dye on electric balance 2. Dissolving all the solid dye in beaker 3. Transfer all the solution into a 500ml volumetric flask 4. Fill up the volumetric flask to the tick mark 5. Prepare standard solutions of 500, 200, 100, 50 and 20 ppm from 1000 ppm stock solution Table 5-1 Preparation of standard solutions STD PPM Stock DI water Total Volume 20 0.2 9.8 10ml 50 0.5 9.5 10ml 1 9 10ml 200 2 8 10ml 500 5 5 10ml 100 6. Vortex vial to complete mix 7. Transfer Standard solutions to cuvette 26 11 mL stock 9 mL dH,0 9 ml dH,O 1 mL 1 mL 1 mL 1 2 3 Stock solution 1/10 Stock solution 0.1/10 = 1/100 Stock solution Figure 5-2 Serial Dilution of unknown samples Wavelength Table 5-3 Absorbance of unknown samples Serial Absorbance Dilution 1 1/10 Sample 1 Sample 2 Sample 3 1/100 Instrument Use 1. Power on instrument (switch is on left side). 2. Turn on monitor and double-click 'Cary win UV' 3. Instrument will run through a start-up check for about 1 minutes. 4. In the toolbar frame, select the "Concentration' icon. 5. In dialog box, enter wavelength 369 nm. a. Choose Abs (absorbance). b. Replicate is 2 6. Click on 'Standard'. a. unit: mg/L b. number of standard and concentration of standard solution 7. Click on 'Sample and enter sample number 8. Click 'OK' 9. Click on Zero icon after insert Blank cuvette into UV slot. 10. Fill cuvette 34 with standard samples and cleaning cuvette surface with chem wipes. 11. Place cuvette in the slot. 12. Click "Start' 13. Record Abs(absorbance) 14. Drawing standard graph 15. Fill cuvette 4 with unknown samples and cleaning cuvette surface with chem wipes. 16. Place cuvette in the slot. 17. Click "Start' 18. Record concentrations 28 8. Measure the transmissivity at a peak measure three times and make a note of your results in your lab notebook 9. Create calibration curves from data. Table 5-2 Absorbance of standard solutions PPM Wavelength Absorbance 2 1 Average 20 50 100 200 500 UV/VIS 1 0.8 0.6 Absorbance 0.4 0.2 0 0 50 100 150 350 400 450 500 200 250 300 Concentration (ppm) Figure 5-1 Calibration curve from standard solutions 5.3 Two steps of a serial dilution and measure the concentrations of unknown samples 1. Pour about 11 ml unknown concentration of methylene blue solution from the bottle to your vial 2. Dilute the dye solution 10 fold by using pipettes : Pipette 1 ml above sample solution to your vial 3. Fill the solution to 10 ml 4. Transfer Standard solutions to cuvette 5. Measure absorbance of each 27 o o o o o Lab report requirement Calculate solution concentration by ppm for all solutions Discuss source of data errors How do you improve your skill to get better accuracy and precision of solution making Describe the key steps of the experiment Attach all the original data and spectrum Abs 0.2- 0.0 1.0 गवाापवा a., Read Zero Abs (369.0 nm) 0.0794 Calibration Collection time 10/25/2018 2:00:04 PM Mean Standard %RSD SD Readings Concentration F g/L Std 1 1.0971 1.0970 1.0 1.0970 0.00007 0.00644 Std 2 0.3021 0.3022 20 0.3022 0.00007 0.02340 I Std 3 0.1331 0.1333 3.0 0.1332 0.00014 0.10617 Std 4 0.0839 0.0840 Clear report 4.0 0.0839 0.00007 0.08423 Recalculate Sid 5 0.0640 0.0640 Print 0.0640 5.0 0.00000 0.00000 Read sequence complete HP Compaq LA2306x
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