An unknown amount of a compound with a molecular mass of 294.46 g/mol is dissolved in...
An unknown amount of a compound with a molecular mass of 284.04 g/mol is dissolved in a 10 mL volumetric flask. A 1.00 mL aliquot of this solution is transferred to a 25 mL volumetric flask, and enough water is added to dilute to the mark. The absorbance of this diluted solution at 347 nm is 0.472 in a 1.000 cm cuvet. The molar absorptivity for this compound at 347 nm is ?347=6023 M−1cm−1. What is the concentration of the...
An unknown amount of a compound with a molecular mass of 270.93 g/mol is dissolved in a 10-mL volumetric flask. A 1.00-mL aliquot of this solution is transferred to a 25-mL volumetric flask and e water is added to dilute to the mark. The absorbance of this diluted solution at 339 nm is 0.517 in a 1 cm cuvette. The molar absorptivity for this compound at 339 nm is esso- 5835 M-1cm-1 (a) What is the concentration of the compound...
An unknown amount of a compound with a molecular mass of 274.11 g/mol 274.11 g/mol is dissolved in a 10 mL volumetric flask. A 1.00 mL aliquot of this solution is transferred to a 25 mL volumetric flask, and enough water is added to dilute to the mark. The absorbance of this diluted solution at 325 nm 325 nm is 0.523 0.523 in a 1.000 cm cuvet. The molar absorptivity for this compound at 325 nm 325 nm is ?...
An unknown amount of a compound with a molecular mass of 259.45 g/mol is dissolved in a 10-mL volumetric flask. A 1,00-mL aliquot of this solution is transferred to a 2 L volumetric flask and o the mark. The absorbance of this diluted solution at 347 nm is 0.468 in a 1 cm cuvette. The molar (a) What is the concentration of the compound in the cuvette? Number b) What is the concentration of the compound in the 10-ml flask?...
C. Problems 1Explain the difference between transmittance, absorbance, and molar absorptivity Which one is proportional to concentration? 2. The absorbance of a 2.3lx 10 M solution of a compound is 0.822 at a wavelength of 266 nm in a 1.00 cm cell. Calculate the molar absorptivity at 266 nm 3. A compound with a molecular weight of 292.16 was dissolved in a 5-ml volumetric flask. A 1.00-mLaliquat was withdrawn, placed in a 10-mL volumetric flask, and diluted to the mark....
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...
A standard solution of iron was made by weighing 0.075 g of Fe(NH4)2(SO4)2 6(H2O) in 250 mL. Aliquots of this standard solution (see below) were transferred to a 100 mL volumetric flask, pH adjusted with citrate, and reacted with hydroquinone and o-phenanthroline and diluted to volume (100 mL). The absorbance was measured in a 1.0-cm cell using a Genesys 20 Spectrophotometer at 508 nm: Aliquot of standard solution Absorbance 1.0 mL 0.079 2.0 mL 0.163 5.0 mL 0.413 10.0 mL...
Question 2 Compound "Y" (molar mass = 480.5 g moll) used as a food coloring. Following experiment was carried out to find the concentration of "Y" in a beverage. A stock solution of compound "Y" (concentration = 7.50 0 10-4 mol L-) was used to prepare a series of standard solutions. Calibrated pipets and 100.0 mL volumetric flasks were used for these preparations. Then, absorbance of these solutions were measured at 460 nm using 1-cm cuvettes. A dilution was carried...
A standard iron solution was prepared by dissolving 0.0100 g of pure iron in acid then transferring to a 50.00 mL volumetric flask with orthophenanthroline as a complexing agent. At a wavelength of 540 nm, the absorbance of the standard was 0.239 in a 1.00 cm cuvette. A 0.149 g sample of an iron ore was crushed and digested in 5 mL of concentrated acid. The digested sample was then transferred to a 10.00 mL volumetric flask and diluted to...
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...