A caffeine sample was diluted by a factor of 1000 and UV-Vis spectra of diluted solution...
A caffeine sample was diluted by a factor of 1000 and UV-Vis spectra of diluted solution showed Absorbance of 0.0340 at 275nm. The concentration of diluted sample was determined as 2.76 × 10-5 Mol. What is the Molar Absorptivity (e) of caffeine at 275nm in both the diluted and concentrated solutions? Consider thickness of a cuvette – 1cm.
Homework Answers
Request Answer!
We need at least 10 more requests to produce the answer.
0 / 10 have requested this problem solution
The more requests, the faster the answer.
Add Answer to:
A caffeine sample was diluted by a factor of 1000 and UV-Vis
spectra of diluted solution...
A caffeine sample was diluted by a factor of 100 and UV-Vis spectra of diluted solution...
A caffeine sample was diluted by a factor of 100 and UV-Vis spectra of diluted solution showed Absorbance of 0.240 at 275nm. The concentration of diluted sample was determined as 2.76 × 10−2 mMol. What is the Molar Absorptivity (e) of caffeine at 275nm in dilute and in concentrated solution? Consider thickness of a cuvette – 1cm.
(10 pts) The iron content of a well water sample is determined by UV-Vis spectroscopy. A...
(10 pts) The iron content of a well water sample is determined by UV-Vis spectroscopy. A 10.00 mL aliquot of well water is transferred to a 100.0-mL volumetric flask and 20 mL of 0.10 M nitric acid is added to oxidize iron (II) to iron (II). Next 30 mL of a 0.1 M sodium thiocyanate solution is added to form the deep red complex iron (II) thiocyanate. The solution is diluted to volume with DI water. A reagent blank is...
(10 pts total) You are going to collect UV-Vis spectra of an unknown solution of beta...
(10 pts total) You are going to collect UV-Vis spectra of an unknown solution of beta carotene (structure given below) dissolved in hexane. a. (5 pts) You have a choice between a quartz cuvette or a Thallium Bromoiodide (KRS-5) cuvette? Which should you choose and why? The following chart may be useful. KRISTIILTH 100 30000 1000 3000 Wavelength, 0 1000 b. (5 pts) How would taking the spectrum in ethanol affect your spectrum? Explain.
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...
Table 1. Concentrations of [Fe(Phen),1?, M, in water and UV- vis absorbance values recorded at 2...
Table 1. Concentrations of [Fe(Phen),1?, M, in water and UV- vis absorbance values recorded at 2 -505 nm. Concentration of [Fe(Phen)/, M Absorbance 9.500 x 10 0.999 4.250 x 10 0.480 0.219 2.125 10% 1.063 x 10 0.104 0.000 0.003 Table 2. UV-vis absorbance values of [Fe(phen)]* held at 35 °C after mixing with H SO, and recorded at 5 minute intervals (in water at max = 505 nm). Time (minutes) Absorbance 0.997 0.935 0.877 0.823 0.772 0.724 0.680 0.638...
Dilution is a process in which the concentration of a solution is lowered by adding more...
Dilution is a process in which the concentration of a solution is lowered by adding more solvent. Some of the reasons dilutions are performed are to minimize measurement errors when preparing a series of solutions at different concentrations, to save time and laboratory space, and to make more accurate measurements on an analytical balance when the target concentration is very low. The new concentration of a diluted solution can be determined from the following equation, sometimes called the dilution equation,...
Question 2 Compound "Y" (molar mass = 480.5 g moll) used as a food coloring. Following...
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...
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...
answer question with full working out please Calcium in a sample solution was determined by atomic absorption spect...
answer question with full working out please
Calcium in a sample solution was determined by atomic absorption spectrophotometry. A 1000 ppm stock solution of calcium was prepared which was then diluted 1:10. Standards were prepared by diluting the second solution, respectively, 1:20, 1:10 and 1:5. The sample solution was diluted 1:25. Strontium chloride was added to all solutions before dilution. Absorbance signals, when the solutions were aspirated into an air-acetylene flame, were as follows: standards, 9.1, 18.6, 37.0; sample 23.9....
the guiding questions. the max absorbance is 460. Guiding questions complex turque . Compare the molar...
the
guiding questions. the max absorbance is 460.
Guiding questions complex turque . Compare the molar absorptivity coefficients you obtained with SCN and Fe" as limiting reagents. Would you expect them to be the same? Why or why not? (Week 1) • The accepted molar absorptivity coefficient for FeSCN is 7.0x10' M'cm''. Find the bias and relative bias of your values and suggest possible sources of errors. (Week 1) • Which molar absorptivity coefficient will you use to calculate the...
(10 pts) The iron content of a well water sample is determined by UV-Vis spectroscopy. A 10.00 mL aliquot of well water is transferred to a 100.0-mL volumetric flask and 20 mL of 0.10 M nitric acid is added to oxidize iron (II) to iron (II). Next 30 mL of a 0.1 M sodium thiocyanate solution is added to form the deep red complex iron (II) thiocyanate. The solution is diluted to volume with DI water. A reagent blank is...
(10 pts total) You are going to collect UV-Vis spectra of an unknown solution of beta carotene (structure given below) dissolved in hexane. a. (5 pts) You have a choice between a quartz cuvette or a Thallium Bromoiodide (KRS-5) cuvette? Which should you choose and why? The following chart may be useful. KRISTIILTH 100 30000 1000 3000 Wavelength, 0 1000 b. (5 pts) How would taking the spectrum in ethanol affect your spectrum? Explain.
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...
Table 1. Concentrations of [Fe(Phen),1?, M, in water and UV- vis absorbance values recorded at 2 -505 nm. Concentration of [Fe(Phen)/, M Absorbance 9.500 x 10 0.999 4.250 x 10 0.480 0.219 2.125 10% 1.063 x 10 0.104 0.000 0.003 Table 2. UV-vis absorbance values of [Fe(phen)]* held at 35 °C after mixing with H SO, and recorded at 5 minute intervals (in water at max = 505 nm). Time (minutes) Absorbance 0.997 0.935 0.877 0.823 0.772 0.724 0.680 0.638...
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...
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...
answer question with full working out please
Calcium in a sample solution was determined by atomic absorption spectrophotometry. A 1000 ppm stock solution of calcium was prepared which was then diluted 1:10. Standards were prepared by diluting the second solution, respectively, 1:20, 1:10 and 1:5. The sample solution was diluted 1:25. Strontium chloride was added to all solutions before dilution. Absorbance signals, when the solutions were aspirated into an air-acetylene flame, were as follows: standards, 9.1, 18.6, 37.0; sample 23.9....
the
guiding questions. the max absorbance is 460.
Guiding questions complex turque . Compare the molar absorptivity coefficients you obtained with SCN and Fe" as limiting reagents. Would you expect them to be the same? Why or why not? (Week 1) • The accepted molar absorptivity coefficient for FeSCN is 7.0x10' M'cm''. Find the bias and relative bias of your values and suggest possible sources of errors. (Week 1) • Which molar absorptivity coefficient will you use to calculate the...
Most questions answered within 3 hours.
-
1) What are the two distinct steps that one needs to perform
when developing a data...
asked 1 second ago -
2) Write a C++ program that uses a class called “Degree” to
obtain the trigonometric
values...
asked 1 hour ago -
1. In eukaryotic cells the genomes of
&
asked 1 hour ago -
The standard enthalpy of propanol (C3H7OH) is -303.0 kJ/mol.
Compute both of the
gross and net...
asked 1 hour ago -
Why PWM using H-bridge for control motor speed is more power
effiecient than the linear amplifier...
asked 1 hour ago -
In 1999, Carly Fiorina famously said,"I hope that we are at a
point that everyone is...
asked 1 hour ago -
Individuals in a species of moth vary in wing color from white to
black, but all...
asked 1 hour ago -
The following standards for variable manufacturing overhead have
been established for a company that makes only...
asked 1 hour ago -
The United States government wanted to determine what proportion
of Americans approve of the current president,...
asked 1 hour ago -
2-N stone is dropped from the top of a cliff. The stone hits the
ground 3...
asked 1 hour ago -
Vitamins participate in metabolic reactions in their coenzyme
forms . Match the following reactions to the respective...
asked 2 hours ago -
We have developed a new mobile device and wish to gain insight
into the price that...
asked 2 hours ago