PART B. Spectrophotometric Determination of the Copper Content of a Penny 3.116 Mass of penny: g 1979 Date on penny: A-l03 17-1/00) Concentration of standard Cu solution: 300 M Volume, Standard Volume, 1 M Cu (mL) [Cu2-] (M) % Transmittance Absorbance 2+ HNO, (mL) (use Eq. 4) 2 00 3,22 3 22 Test tube 1 800 S00 S.00 2.82 Test tube 2 OIS Z.82 &.00 2 2.619 O. 24 Test tube 3 2o19 2.5S 2.55 O.300 Standard 2.60 2.l09 Unknown X - lg - log o.is/iou) log Co.74/100) 73 Concentration of Cu in unknown (penny) O 201 M (from calibration curve) Mass of Cu in sample (penny) . Recall that the volume of the solution obtained by dissolving the penny is 250.00 mL (0.25000 L). To calculate the mass of Cu in the penny, you will first need to calculate the moles of Cu. This is done by multiplying the concentration of Cu (in moles/L) by the volume (0.25000 L). Finally, multiplying the moles of Cu by the molar mass of Cu (in g/mole) yields the mass of Cu in the original sample. 128 % Percent Cu in penny = Remember that percent by mass is simply the mass of Cu in the sample divided by the total mass of the sample (X 100 %). Show your calculations in the space below. Attach the calibration curve to this page. O.204 U 250OL O.810 0.0128

Tablet powder containing 100mg of promazine hydrochloride is ground to a paste  with 10 ml of 2 M HCl. The paste is then diluted with 300 ml of water, shaken for  15 min and finally made up to 500 ml. A portion of the extract is filtered. Then,  5 ml of the filtrate is taken and diluted to 200 ml with 0.1 M HCl.  – Absorbance reading=0.855 is read at a wavelength wavelength of 251 nm  – a (1%, 1 cm) value of promazine.HCl at 251 nm=950  – Stated content of promazine.HCl per tablet=60 mg  – Weight of 24 tablets=1.500g  – Weight of tablet powder taken for assay=180 mg expected content in tablet taken is:   172.8 mg 1000mg 100 mg 100g   Concentration in diluted tablet extract is:   0.1g/mL 0.9 g/100ml 1.11 g/mL 0.9 mg/100ml       Concentration in original  tablet extract is:   36g/mL 36 mg/100ml 19.38 mg/100ml 16.15 mg/mL     Amount of  promazine.HCl in original extract is:   172.8mg 180mg/100ml 96.90mg 180mg     percentage of stated content 99.1 % 96% 80.75mg/100ml 104.2%

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Tablet powder containing 80 mg of promazine hydrochloride is ground to a paste with 10 ml of 2 M HCl. The paste is then diluted with 200 ml of water, shaken for 15 min and finally made up to 500 ml. A portion of the extract is filtered. Then, 5 ml of the filtrate is taken and diluted to 120 ml with 0.1 M HCl.  – Absorbance reading=0.755 is read at a wavelength wavelength of 251 nm  – A (1%, 1 cm) value of promazine.HCl at 251 nm=935  – Stated content of promazine.HCl per tablet=50 mg  – Weight of 20 tablets=1.667 g  – Weight of tablet powder taken for assay=163 mg expected content in tablet taken is:   A-97.78 g/mL B-97.78 g/100ml C-0.0097g/mL D-97.78 mg/100ml   Concentration in diluted tablet extract is:   A-0.81g/mL B-80 g/100ml C-0.00081g/mL D-0.807 mg/100ml       Concentration in original  tablet extract is:   A-19.38g/mL B-16.15 mg/100ml C-19.38 mg/100ml D-16.15 mg/mL     Amount of  promazine.HCl in original extract is:   A-96.90mg B-80.75mg C-96.90mg/100ml D-80.75mg/100ml…