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A chemist needs to create a series of standard Cu" (aq) solutions for an absorbance experiment....
A chemist needs to create a series of standard Cu- (aq) solutions for an absorbance experiment....
A chemist needs to create a series of standard Cu- (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 20.00 mL of a 2.64 M Cup (aq) stock solution to a 500.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 25.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to...
A chemist needs to create a series of standard Cu²+ (aq) solutions for an absorbance experiment....
A chemist needs to create a series of standard Cu²+ (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 25.00 mL of a 2.20 M Cu2+ (aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 5.00 mL of the second solution to a 50.00 ml. volumetric flask, and he adds enough water to dilute to...
A chemist needs to create a series of standard Cu2+ (aq) solutions for an absorbance experiment....
A chemist needs to create a series of standard Cu2+ (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 10.00 mL of a 2.68 M Cu2+ (aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 50.00 mL volumetric flask, and he adds enough water to dilute to...
A stock solution of Cu2+(aq) was prepared by placing 0.9157 g of solid Cu(NO3)2∙2.5 H2O in...
A stock solution of Cu2+(aq) was prepared by placing 0.9157 g of solid Cu(NO3)2∙2.5 H2O in a 100.0-mL volumetric flask and diluting to the mark with water. A standard solution was then prepared by transferring 2.00 mL of the stock solution to a second 25.00-mL volumetric flask and diluting to the mark. What is the concentration (in M) of Cu2+(aq)in the stock solution? What is the concentration (in M) of Cu2+(aq)in the standard solution?
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The dat...
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The data is as following: Concentration (ppm) 10.0 20.0 30.0 40.0 50.0 Absorbance 0.105 0.198 0.330 0.402 0.533 An unknown solid sample (0.1050 g) containing substance X was dissolved in 5.0 mL acidic solution and then transferred to a 100.0 mL volumetric flask and filled with deionized water to the mark. The absorbance of this solution is 0.378. What is...
3. Experimental Procedure, Part A.1. For preparing a set of standard solutions of FeNCS, the equilibrium...
3. Experimental Procedure, Part A.1. For preparing a set of standard solutions of FeNCS, the equilibrium molar con- centration of FeNCS is assumed to equal the initial molar concentration of the SCN in the reaction mixture. Why is this assumption valid? A. A Set of Standard Solutions to Establish a The set of standard solutions is used to determine the absorbance of known molar con- centrations of FeNCS2. A plot of the data, known as a calibration curve, is used...
THE DETERMINATION OF IRON BY SPECTROPHOTOMETRY INTRODUCTION In this experiment, the red-orange colored complex formed between...
THE DETERMINATION OF IRON BY SPECTROPHOTOMETRY INTRODUCTION In this experiment, the red-orange colored complex formed between iron(II) and 1,10- phenanthroline (Eqn.) is used in determination of iron by spectrophotometry. Fe+3PhenH Fe(Phen)2 +3H red-orange (A 512 nm) An excess of reducing reagent, such as hydroxylamine or hydroquinone, is often used to reduce and maintain iron in +2 oxidation state. The complex, once formed, is very stable, and can be stored for a long time. Required Reading: Skoog and West (9E): Chapter...
need help on these Suppose you obtained the following data from two standard solutions of known...
need help on these
Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
To analyze the chromium in an unknown sample 1.5623 f of the sample was pretreated and...
To analyze the chromium in an unknown sample 1.5623 f of the sample was pretreated and diluted to the exact 100 mL mark in a volumetric flask. Two 20.0 mL samples of this solution were taken. In the first sample, a Cr-EDTA complex is developed and sufficient water is added to give a total volume of 100.0 mL. In the second sample, 10.0 mL of Cr(III) standard solution at to concentration of 15 mM was added before developing the Cr-EDTA...
You prepared standard benzoic acid and caffeine solutions that allowed you to produce four standard curves...
You prepared standard benzoic acid and caffeine solutions that allowed you to produce four standard curves with the linear equations listed below. You also diluted an unknown solution by taking a 4 mL aliquot with a volumetric pipet and transferring it into a 100 mL volumetric flask that contained 10 mL of 0.10 M HCl. You then diluted it to the mark with Dl water. You measured the absorbance at both wavelengths for the diluted unknown. The data is shown...
A chemist needs to create a series of standard Cu- (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 20.00 mL of a 2.64 M Cup (aq) stock solution to a 500.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 25.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to...
A chemist needs to create a series of standard Cu²+ (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 25.00 mL of a 2.20 M Cu2+ (aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 5.00 mL of the second solution to a 50.00 ml. volumetric flask, and he adds enough water to dilute to...
A chemist needs to create a series of standard Cu2+ (aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 10.00 mL of a 2.68 M Cu2+ (aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 50.00 mL volumetric flask, and he adds enough water to dilute to...
2. The absorbance of a series of standard solutions of a substance X vs concentration [X], in ppm) is measured. The data is as following: Concentration (ppm) 10.0 20.0 30.0 40.0 50.0 Absorbance 0.105 0.198 0.330 0.402 0.533 An unknown solid sample (0.1050 g) containing substance X was dissolved in 5.0 mL acidic solution and then transferred to a 100.0 mL volumetric flask and filled with deionized water to the mark. The absorbance of this solution is 0.378. What is...
3. Experimental Procedure, Part A.1. For preparing a set of standard solutions of FeNCS, the equilibrium molar con- centration of FeNCS is assumed to equal the initial molar concentration of the SCN in the reaction mixture. Why is this assumption valid? A. A Set of Standard Solutions to Establish a The set of standard solutions is used to determine the absorbance of known molar con- centrations of FeNCS2. A plot of the data, known as a calibration curve, is used...
THE DETERMINATION OF IRON BY SPECTROPHOTOMETRY INTRODUCTION In this experiment, the red-orange colored complex formed between iron(II) and 1,10- phenanthroline (Eqn.) is used in determination of iron by spectrophotometry. Fe+3PhenH Fe(Phen)2 +3H red-orange (A 512 nm) An excess of reducing reagent, such as hydroxylamine or hydroquinone, is often used to reduce and maintain iron in +2 oxidation state. The complex, once formed, is very stable, and can be stored for a long time. Required Reading: Skoog and West (9E): Chapter...
need help on these
Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
To analyze the chromium in an unknown sample 1.5623 f of the sample was pretreated and diluted to the exact 100 mL mark in a volumetric flask. Two 20.0 mL samples of this solution were taken. In the first sample, a Cr-EDTA complex is developed and sufficient water is added to give a total volume of 100.0 mL. In the second sample, 10.0 mL of Cr(III) standard solution at to concentration of 15 mM was added before developing the Cr-EDTA...
You prepared standard benzoic acid and caffeine solutions that allowed you to produce four standard curves with the linear equations listed below. You also diluted an unknown solution by taking a 4 mL aliquot with a volumetric pipet and transferring it into a 100 mL volumetric flask that contained 10 mL of 0.10 M HCl. You then diluted it to the mark with Dl water. You measured the absorbance at both wavelengths for the diluted unknown. The data is shown...
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