Concept explainers
(a)
Interpretation:
The materials as well as instrument components required for making an instrument used to investigate the absorption bands in the given range of wavelength.
Concept introduction:
Spectral lines help in identifying the atoms and molecules. These are result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
(b)
Interpretation:
The materials as well as instrument components required for making an instrument used to obtain the absorption spectra in far IR − 20 to 50 µm needs to be suggested.
Concept introduction:
Spectral lines help in identifying the atoms and molecules. These are result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
(c)
Interpretation:
The materials as well as instrument components required for making an instrument used to make a portable device to determine the iron content in natural water depending on absorption of radiation by red Fe(SCN)2+ complex needs to be suggested.
Concept introduction:
Spectral lines are lines which help in identifying the atoms and molecules. These are a result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
(d)
Interpretation:
The materials as well as instrument components required for determination of nitrobenzene in air samples depending on absorption peak at 11.8µm needs to be suggested.
Concept introduction:
Spectral lines are lines which help in identifying the atoms and molecules. These are a result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
(e)
Interpretation:
The materials as well as instrument components required for making an instrument used to determine the wavelength of flame emission lines for metallic elements in 200 nm to 780 nm region needs to be suggested.
Concept introduction:
Spectral lines are lines which help in identifying the atoms and molecules. These are a result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
(f)
Interpretation:
The materials as well as instrument components required for making an instrument used for spectroscopic studies in vacuum UV region needs to be suggested.
Concept introduction:
Spectral lines are lines which help in identifying the atoms and molecules. These are a result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
(g)
Interpretation:
The materials as well as instrument components required for making an instrument used for spectroscopic studies in the near IR region needs to be suggested.
Concept introduction:
Spectral lines are lines which help in identifying the atoms and molecules. These are a result of absorption or emission of light in a comparatively narrower frequency range compared to the frequencies nearby.
Spectral region consists of different wavelengths which are distinguished based on the sources used to produce them and detect the different wavelengths.
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Chapter 7 Solutions
Principles of Instrumental Analysis
- A Dubosq colorimeter consists of a cell of fixed path length and a cell of variable path length. By adjusting the length of the latter until the transmission through the two cells is the same. the concentration of the second solution can be inferred from that of the former. Suppose that a plantdye of concentration 25 μg dm-3 is added to the fixed cell. the length of which is 1.55 em. Then a solution of the same dye. but of unknown concentration. is added to the second cel l. It is found that the same t ransmittance is obtained when the length of the second cel l is adjusted to 1.18 em. What is the concentration of the second solution?arrow_forwardThe following data have been obtained in the calibration of a series of standards for the determination of iron, measuring the transmittance, at 506 nm and thickness of 1.00 cm of iron (II) solutions in which color with 1.10 has been developed -phenanthroline. [Fe] (ppm) 0.20 0.40 0.60 0.80 1.00 2.00 3.00 4.00 5.00 6.00 7.00 T (%) 90.0 82.5 76.0 69.5 63.5 41.0 26.3 17.0 10.9 7.0 4.5 Calculate the mean molar absorptivity of iron when determined by this method.arrow_forward(i) The detection of Mn by graphite furnace atomic absorption spectrometry (GFAAS) is sensitive to the presence of aluminium ions Al3+ which may form refractory compounds such as MnAl2O4. Comment on the possible impact of this compound on the measurements and what action may be taken to minimize this. (ii) Write a brief note on the best practice for the preparation of a calibration curve. (iii) Atomic absorption spectroscopy (AAS) is a powerful technique for the analysis of trace amounts of metals. Describe the two common atomic absorption methods used in the lab with reference to their comparative strengths and weaknesses.arrow_forward
- Mercury(II) forms a 1:1 complex with triphenyltetrazolium chloride that exhibits an absorption maximum at 255 nm. The mercury(II) in a soil sample was extracted into an organic solvent containing an excess of TTC , and the resulting solution was diluted to 100.0 mL in a volumetric flask. Five-milliliter aliquots of the analyte solution were then transferred to six 25-mL volumetric flasks. A standard solution was then prepared that was 5*10^-6 M in . Volumes of the standard solution shown in the table were then pipetted into the volumetric flasks, and each solution was then diluted to 25.00 mL. The absorbance of each solution was measured at 255 nm in 1.00-cm quartz cells. Please solve and explain these questions: A.) Enter the given data pictured above into a spreadsheet and show the correct standard additions plot B.) Determine the slope and the intercept of the line C.)Determine the standard deviation of the slope and the intercept. D.) Calculate the concentration of Hg(II) in the…arrow_forwardThe accuracy of a spectrophotometer can be evaluated by preparing a solution of 60.06-ppm K2Cr2O7 in 0.0050 M H2SO4 and measuring its absorbance at a wavelength of 350 nm using a cell with a pathlength of 1.00 cm. The absorbance should be 0.640. What is the molar absorptivity of K2Cr2O7 at this wavelength?arrow_forwardYou are working with metal thiocyanate complex, M(SCN)+, with a molar absorptivity constant, ε, of 2700 cm−1M−1 at 500 nm. If you are is using a 1.00 cm cuvette for absorbance measurements at 500 nm, what concentration of M(SCN)+ will give an absorbance value of 0.280?arrow_forward
- When measured in a 1-cm cell, an 8.50 x 10-5 M solution of species A exhibited absorbances of 0.129 and 0.764 at 475 and 700 nm, respectively. A 4.65 x 10-5 M solution of species B gave absorbances of 0.567 and 0.083 under the same circumstances. Calculate the concentrations of A and B in solutions that yielded the following absorbance data in a 1.25 cm cell : 0.502 at 475 nm and 0.912 at 700 nm. Pls answer need help.arrow_forwardMixing the chelating reagent B with Ni(II) forms the highly colored NiB22+, whose solutions obey Beer’s lawat 395 nm overa wide range. Provided the analytical concentration of the chelating reagent exceeds that of Ni(II) by a factor of 5 (or more), the cation exists, within the limits of observation, entirely in the form of the complex. Use the accompanying data to evaluate the formation constant Kf for the process Ni2++2BNiB22+arrow_forwardAtomic absorption spectroscopy with graphite furnace atomization is an extremely sensitive technique. The standard addition method is used with this technique to determine the concentration of copper in urine. A 20.00 mL sample of urine is spiked with 1.00 mL of 300. ppb Cu²+ and this mixture gives a response of 0.168. Another 1.00 mL aliquot of 300. ppb Cu²+ is added to this mixture and gives a reading of 0.235Determine the concentration of copper in the urine samplearrow_forward
- A standard solution was put through appropriate dilutions to give the concentrations of iron shown in the table that follows. The iron(II)-1,10-phenanthroline complex was then formed in 25.0-mL aliquots of these solutions, following which each was diluted to 50.0 mL. The following absorbances (1.00-cm cells) were recorded at 510 nm: Calculate the concentration, in ppm, of a sample with an abosrbance of 0.829. Fe(II) concentration (ppm) A510 4.00 0.160 10.0 0.390 16.0 0.630 24.0 0.950 32.0 1.260 40.0 1.580arrow_forwardPd(II) and Au(II) can be determined simultaneously by the reaction with methiomeprazine (C 19 H 24 N 2 S 2 ). The maximum absorption for Pd occurs at 480 nm, while for the Au complex it is at 635 nm. A sample of 25 mL was treated with excess of the complexant and then diluted to 50.0 mL. Calculate the molar concentrations of Pd(II) and Au(II) in the sample. The data are found in the table below and the bucket used was 1.0 cm.arrow_forwardOne 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 Standardarrow_forward
Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
Chemistry for Engineering StudentsChemistryISBN:9781285199023Author:Lawrence S. Brown, Tom HolmePublisher:Cengage Learning