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

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

Appl Of Ms Excel In Analytical Chemistry

2nd Edition

ISBN:9781285686691

Author:Crouch

Publisher:Crouch

Chapter12: Spectrochemical Methods

Section: Chapter Questions

Problem 10P

See similar textbooks

Similar questions

A stock solution of analyte is made by dissolving 34.83 mg of copper (II) acetate hexahydrate(fw = 289.73 g/mol) in 25.00 mL of water. A second stock solution of internal standard is madeby dissolving 28.43 mg of germanium (I) acetate (fw = 190.74 g/mol) into 25.00 mL of water.These solutions are used to make a series of standards for ﬂame atomic absorption analysiscalibration. The standard solutions (each 10.00 mL total volume) should have the followingconcentrations of copper: 10.00; 25.00; 50.00; 100.0; and 200.0 μM. Each calibration solutionshould also contain 50.00 μM of germanium. What is the analyte stock solution concentration? What is the internal standard stocksolution concentration?Complete this table.
A third spectrophotometric method for the quantitative analysis of Pb2+ in blood uses Cu2+ as an internal standard. A standard containing 1.75 ppb Pb2+ and 2.25 ppb Cu2+ yields a ratio of (SA/SIS)std of 2.37. A sample of blood is spiked with the same concentration of Cu2+, giving a signal ratio, (SA/SIS)samp, of 1.80. Determine the concentration of Pb2+ in the sample of blood.
a solution of 5.47 ppm kmno4 has a transmittance of 0.409 in a 1 cm at 520nm. Calcualate the molar absorptivity of KMnO4 Express in 5 SF
Using the absorbance of [FeSCN]+2 at the wavelength of maximum absorption which you obtained in part B, and the diameter of the tube, obtained in part A,calculate the molar extinction coefficient. given info: Concentration of Fe3+ stock solution, C1 = 0.001 M Volume of stock Fe3+ solution pipetted, V1 = 25mL Concentration of diluted stock solution, C2 = 0.0004 M Volume of Fe2+ solution and KSCN (upon mixing) = 10mL Weight of KSCN = 1g The reaction taking place is given as: The reaction taking place is given as: F e 3+ (aq) + SC N − (aq) ⇔Fe [SCN] 2+ (aq) the concentration of [FeSCN]2+ after the mixing of Fe3+ and SCN- is 2.5 x 10-3 M. Moles of [FeSCN]2+ = 2.5 x 10-5 moles Diameter:1.2cm The wavelength at which maximum absorption takes place is = 480 nm
A spectrophotometer method for the quantitative analysis of Pb2+ in blood uses Cu2+ as an internal standard. A standard containing 1.75 ppb Pb2+ and 2.25 ppb Cu2+ yields a signal of 0.832 for Pb2+ and a signal of 0.351 for Cu2+. A sample of blood is spiked with the same concentration of Cu2+, giving a signal of 0.520 for Pb2+ and 0.289 for Cu2+. Determine the concentration of Pb2+ in the sample of blood.
An aqueous solution of a Ni2+ complex with a concentration of 8.61 × 10–5 M was analyzed by a UV-VIS spectrometer at 470 nm and in a 1.00-cm cell; a percent transmittance value of 78.70% was recorded. What is the absorbance of the solution? * Provide your answer with three decimal places and without units. Avoid using scientific notation.
In an analysis of chromium in steel containing 1.76% Cr. 0.5000 g of that steel is weighed and dissolved in acid, whereupon the Cr is oxidized to Cr2O72- (dichromate), and blunt to a volume of 250 mL. A 10 mL aliquot of this solution is diluted with water and acid to a final volume of 100 mL. The resulting solution shows a transmittance of 41.7% in a 1 cm pathlength cell. When a 0.7500 g sample of unknown steel is dissolved in acid, oxidized, and diluted to 250 mL, the resulting solution exhibits a transmittance of 61.3% under identical experimental conditions. What is the percentage of Cr in the steel?
2. a. State TWO (2) advantages of Inductively coupled plasma-optical emissionspectroscopy (ICP-OES) over Flame atomic absorption spectrosocpy (FAAS). b. What are the TWO (2) advantages of graphite furnace AAS (GFAAS)over flame AAS (FAAS)? c.
(a) A sample of body serum is to be analysed for sodium by flame emission spectroscopy. 1.00cm3 aliquot of serum was pipetted into each of two 50.0 cm3 volumetric flasks. The firstflask was diluted to volume with deionised water. The absorbance of this first solution was0.350. To the second flask 10.0 cm3 of a 25.0 ppm sodium standard was added and theflask made up to volume with deionised water. The absorbance of this second solution was0.720.(i) Calculate the concentration of the sodium in the body serum in mg dm–3
A water sample was run through the colorimetric procedure for the analysis of nitrate, giving 65.0% transmittance. A sample containing 1.00 ppm nitrate run through the exactly the same/identical procedure gave 24.6% transmittance. What was the concentration of nitrate in the first sample?
A spectrophotometric method for the quantitative analysis of Fe2+ in blood uses Zn2+ as an internal standard. A sample containing Fe2+ and Zn2+ with final concentration of 3.25 ppb and 0.75 ppb, respectively, that yields a signal of 0.423 for Fe2+ and 0.650 for Zn2+. Subsequently, a sample of blood is spiked with Zn2+ to give the same final concentration and yielded a signal of 0.832 for Zn2+ and 0.110 for the unknown concentration of Fe2+. Determine the concentration of Fe2+ in the sample of blood.
One dietary supplement capsule weighing 4.90 was ground into a fine powder. Two portions of the solid, both weighing 0.200 g, were dissolved in dilute acid, and transferred to 50-mL volumetric flask. To one of these, 5.00 mL of 40.0 ppm manganese ion was added, then both flasks were diluted to the mark with distilled water. When aspirated into the flame of an atomic absorption spectrometer set at a manganese absorption wavelength, the absorbances of the unknown and unknown plus standard were 0.300 and 0.650, respectively. What is the type of calibration method used? a) Standard Addition b) Internal Standard c) External Standard