unknown? 11. Triclosan is an antibacterial compound with an absorbance maximum at 293 nm. A student prepared a calibration curve by measuring five standard solutions of the triclosan in a cuvette with a path length of 5.00 cm. The calibration curve is shown below. (a) Determine the molar absorptivity of triclosan at 293 nm. (b) The absorbance of an unknown sample is measured at 293 nm in a 1.00 cm cell. The absorbance was 0.111. What is the concentration of triclosan in the unknown? (c) What is the absorbance and transmittance of a triclosan sample with a concentration of 0.000840 M measured in a 5.00 cm cuvette? Triclosan calibration curve Absorbance at 293 nm 0.25- 0.2- 0.15- 0.1- 0.05- 0 0 0.0002 0.0004 0.0006 0.0008 0.001 [triclosan] 0.0012 The equation for the line is y = 204.5x

unknown? 11. Triclosan is an antibacterial compound with an absorbance maximum at 293 nm. A student prepared a calibration curve by measuring five standard solutions of the triclosan in a cuvette with a path length of 5.00 cm. The calibration curve is shown below. (a) Determine the molar absorptivity of triclosan at 293 nm. (b) The absorbance of an unknown sample is measured at 293 nm in a 1.00 cm cell. The absorbance was 0.111. What is the concentration of triclosan in the unknown? (c) What is the absorbance and transmittance of a triclosan sample with a concentration of 0.000840 M measured in a 5.00 cm cuvette? Triclosan calibration curve Absorbance at 293 nm 0.25- 0.2- 0.15- 0.1- 0.05- 0 0 0.0002 0.0004 0.0006 0.0008 0.001 [triclosan] 0.0012 The equation for the line is y = 204.5x

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter14: Applications Of Ultraviolet-visible Molecular Absorption Spectrometry

Section: Chapter Questions

Problem 14.10QAP: The acid-base indicator HIn undergoes the following reaction in dilute aqueous solution:...

See similar textbooks

Similar questions

6. Blue Blue dye stock solution 0.293 M Absorbance at 630 nm 0.00265 Calibration curve y = 0.0833x A solution is prepared by diluting 2.79 mL of the blue dye stock solution to 25.00 mL. The measured absorbance for the prepared solution is listed in the data table. (a) What is the theoretical molar concentration? [Blue]theoretical x 10 |M (b) What is the experimental molar concentration? [Blue]experimental x 10 M (c) What is the percent error? Percent error (blue) = %
Caffeine, C8H10O2N4 H2O (MW = 212.2 g/mol) has been shown to have an average absorbance of 0.644 for a concentration of 1.783 mg per 100 mL at 272 nm. A sample of 3.658 g of a soluble coffee product was mixed with water to a volume of 500 mL and a 25 mL aliquot was transferred to a flask containing 25 mL of 0.1 M H2SO4. This was subjected to the prescribed clarification treatment and made up to 500 mL. A portion of this treated solution showed an absorbance of 0.666 at 272 nm. Assumbe b = 1.0 cm. Calculate the % caffeine (w/w) in the sample.
3
The drug tolbutamide (MW 270.0g/mol), a treatment for type 2 diabetes, has a molar absorptivity of 703 /M/cm at 262nm. One tablet was dissolved in 250ml of water. A 10.0 ml aliquot of this solution was diluted to 100.00 ml in a volumetric flask. This diluted solution exhibited an absorbance of 0.275 at 262 nm in a 1.00 cm cell. What is the mass of tolbutamide in the tablet?
Tonic water (20.0 mL) was added into each of two volumetric flasks (100 mL). The first flask was made up to volume with deionised water and produced an absorbance of 0.200. To the second flask was added an aliquot (20.0 mL) of a quinine standard solution (20.0 ppm) and after being made up to volume this produced an absorbance of 0.400. What is the concentration of quinine in the tonic water? a. 8.00 ppm b. 800 ppm С. 40.0 ppm d. 400 ppm е. 20.0 ppm
2. Answer ALL parts. (a) The absorbance of compound A was measured in a 1.00 cm cuvette at 238 nm. A 3.96 x 10 M solution of compound A exhibited an absorbance of 0.624. A blank solution containing only the solvent had an absorbance of 0.029 at the same wavelength. Calculate the molar absorptivity of compoundA in m' mole". (i) The absorbance of an unknown solution of Compound A in the same solvent and cuvette was 0.375 at 238 nm. Find the concentration of A in the unknown. (iii) A concentrated solution of Compound A in the same solvent was diluted from an initial volume of 2.00ml to a final volume of 25 ml and then had an absorbance of 0.733 under the same conditions. What is the concentration of A in the concentrated solution? (iv) What type of cuvette was used in the above analysis? Justify your answer. (b) Name ONE advantage and ONE disadvantage of a linear photodiode array detector compared to a traditional photomultiplier based spectrometer. (c) Why is an FTIR spectrum digital in…
A solution is prepared by diluting 2.79 mL of the blue dye stock solution to 25.00 mL. The measured absorbance for the prepared solution is: Blue dye stock solution = 0.293 M Absorbance at 630 nm = 0.00265 Calibration curve y = 0.0833x A.) What is the theoretical molar concentration? B.) What is the experimental molar concentration? C.) What is the percent error?
A student prepared four standard solutions of (NH4)2Fe(SO4)2 and measured their absorbance at 505 nm. She created a calibration plot with the best-fit line of y = 9372 x + 0.0539. She measured the absorbance of her diluted unknown sample solution as (4.69x10^-1) nm. If she prepared her diluted sample solution by diluting 10.00 mL of the original solution to a total volume of 50.00 mL with deionized water, what is the concentration of Fe2+ in her original solution? Answer in units of M. Note: Your answer is assumed to be reduced to the highest power possible.
A 4.84×10−5 M sample of compound X in a solvent has an absorbance of 0.213 at 528 nm in a 1.000 cm cuvette. The solvent alone has an absorbance of 0.064. What is the molar absorptivity of compound X?
What is the absorbance of a 2.33×10−4M2.33×10−4M solution of a compound with a molar absorptivity of 1.05×103M−1cm−11.05×103M−1cm−1 in a 1.00 cm cell?
The nitrite in a series of standard solutions (mg/L, n = 5) are converted to azo dye and the slope of the calibration curve is 2.0 ppm1. A 10.00-mL mineral water sample is treated in the same way as standards and diluted to a final volume of 100.00-mL. It gives an absorbance of 0.80. The absorbance of blank solution under the same conditions is 0.10. Calculate ppm (mg/L) of NO2 (46 g/mol) and the molarity of NANO2 (69 g/mol) in the original sample
Suppose that a solution has an absorbance of 0.250 at a wavelength of 450 nm. If the concentration of the solution is 22 μM, what is the value of the molar absorptivity? The data were taken with a standard 1-cm cuvette. molar absorptivity in (L cm^−1 mol^-1):