Question

Hi, I need checking on all the work. If anything is wrong then show me step by step how is done.

11. Obtain a Cu 2 solution of unknown concentration. Write the unknown number on the data sheet. 12. Measure the absorbance of your standard solution, the two dilutions, and the unknown solution. Record these readings on the data sheet. All measurements will be made in the same cuvette and with the instrument set at a wavelength of 630 nanometers (nm). Note: 630 nm is the wavelength of visible light at which Cu" absorbs the most. Using the wavelength of maximum absorbance provides data with the greatest reproducibility and accuracy IV. DETERMINING THE CONCENTRATION OF THE UNKNOWN SOLUTION Your instructor will show you how to construct a graph from experimental data 13. Plot absorbance on the Y axis and concentration on the X axis 14. Decide on the scales for each axis. The concentration of highest absorbance (.e. the standard solution) should go at least half way across and halfway up the paper. 15. Plot the three points precisely in their correct positions. 16. Draw the best possible average straight line using the three points as a guide. The only point that the line must pass through is the origin. Hand in the graph with the data sheet. 17. Find the measured absorbance of your unknown on the Y axis. Move straight across to the experimental line. Move straight down to the X axis and record on the data sheet the molarity of the unknown Cu" solution. OPTIONAL: Find the slope of the straight line. Divide the absorbance by the slope to determine the concentration of the unknown. Exp. 6.3

Answer 1

Civen mass untnoun- 0 57 prtssue 741 to 0.978 atm Tempeatuse (T95ct3 vetame 845 ml 0.0821 Latm motk 245X1L -3 R-9as constant Solution wrT n-no motes di at gas equation PV- nRT PV 0.978 atm 2451 n = RT O-0821 Latrmet368 K 7-131X103 Moles Molar mass 0.715 mass 96.45 jmet :. melar masS -131X163 moletalos w'ht untnoun compturd 16.45 3 Imet, the as is ee eledid tao dps Condinde in BUustin-1, mass -sed liquid (mass 1a dnps 00) hut meltculas weisht 9 tau dscalas weht jas = C0-765-0-010) a 0.695 hur mtlacales wght gas y 0.695 . . = 81.63 met 9.131X10 (Map-M.7 Mr 1 XID 96-45-83631 XI D 10.1 87.63

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