Concept explainers
(a)
Interpretation:
Mass absorption coefficient of a solution containing
Concept introduction:
Mass absorption coefficient (
Mass absorption coefficient (
Contribution of “element A” to the mass absorption coefficient of a sample can be written as
Where,
Therefore, the mass absorption coefficient (
In order to calculate mass fractions of each element in a sample, the atomic mass of each element and the molar mass of each compound should be known.
(b)
Interpretation:
Transmitted fraction of the radiation when the Mo
Concept introduction:
Beer’s law can be written as follows, in which, mass absorption coefficient (
Transmittance (T) of a medium is the fraction of incident radiation transmitted by the medium.
Therefore, transmittance can be rewritten as:
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Chapter 12 Solutions
Principles of Instrumental Analysis
- A magnesium-24 ion has a positive charge that is double the charge of a proton, and a mass of 3.98 ✕ 10−26 kg. At a particular instant, it is moving with a speed of 5.00 ✕ 106 m/s through a magnetic field. At this instant, its velocity makes an angle of 58° with the direction of the magnetic field at the ion's location. The magnitude of the field is 0.190 T. (a) What is the magnitude of the magnetic force (in N) on the ion? N (b) What is the magnitude of the ion's acceleration (in m/s2) at this instant? m/s2arrow_forward. In the photobromination of cinnamic acid, using radiation at 420 nm with an intensity of 1.4 x 10 3 Js" and 70% light absorption in a liter of solution for a period of 15 min the concentration of Br, decreased by 0.075 mol.L:1 during this period. What is the quantum yield of the product formation?arrow_forwardNote: The Emission Intensity of the original solution is not given since the calibration method is standard addition.arrow_forward
- Photobromination of cinnamic acid to dibromocinnamic acid was carried out in blue light of wavelength 440nm at 35degree celsius using light intensity of 1.5 *10 power -3 joule per second. An exposure of 20 minutes produces a decrease of 0.075 millimoles of bromine. The solution absorb 80% of light passing through it. Calculate the quantum yield of the reaction.arrow_forward(A) Calculate the wavelength in nm of an emission line of cadmium with a frequency of 1.311 x 1015 Hz. (B) Calculate the wavenumber in cm-1 of an infrared absorption peak with an associated energy of 5.656 x 10-20 J. Report answers to 4 sig figsarrow_forwardAbsorbance at 453 nm 8393939 7 fl. oz./20 ml Beer-Lambert's Law (Spectrophotometry) #1 Fe (aq) + KSCN(s) FESCN "(aq) + K" (aq) 3+ To determine the moles of Fe (aq) in a 100. mL sample of an unknown solution, excess KSCN(s) is added to convert all the Fe (aq) into the dark red species FeSCN"(aq), as represented by the equation above. The absorbance of FESCN"(aq) at different concentrations is shown in the graph below. 2+ 0.50 目0.40 0.30 0.20 01 0. 0. 5 x 10-5 10 x 10-5 Concentration of FESCN2+ (M) If the absorbance of the mixture is 0.20 at 453 nm, haw many moles of Fe (aq) were present in the 100. mL sample? (Assume that any volume change due to adding the KSCN(s) Iis negligible.) 3+, 4x10-4 mol 3 x 104 mol (B) 4x 10-6 mol 3x 10-6 molarrow_forward
- Covalent bonds in a molecule absorb radiation in the IR region and vibrate at characteristic frequencies. (a) The C---O bond absorbs radiation of wavelength 9.6 mm. What frequency (in s-1) corresponds to that wavelength? (b) The H---Cl bond has a frequency of vibration of 8.652x1013 Hz. What wavelength (in mm) corresponds to that frequency?arrow_forwardThe spin quantum number of a nitrogen-14 nucleus isI= 1. What would be the nuclear magnetic resonance spectrum for a proton resonance line that was split by interactionwith (a) two. (b) three equivalent nitrogen-14 nuclei?arrow_forwardThe first excited state of Ca is reached by absorption of 422.7-nm light. (a) What is the energy difference (J) between the ground and excited states? (b) The degeneracies are g*/g0 3 for Ca. Find N*/N0 at 2 500 K. (c) By what percentage will the fraction in (b) be changed by a 15-K rise in temperature? (d) Find N*/N0 at 6 000 K.arrow_forward
- (b) A compound having molecular weight 151.163 g/mol is determined in a sample. A 0.0302 g sample was dissolved in an aqueous solvent and diluted the solution to 1 L. The solution has A max at 243 nm (ɛ=2.6×104 cm1 mol1 L). The solution exhibits an absorbance of 0.642 in a 2 cm cell. Calculate the percentage of the above compound in the sample.arrow_forwardFf.238.arrow_forwardThe molar absorptivity for the FD&C dye “Red No. 3” (Erythrosine) 8.25104 M‒1·cm‒1 at 526 nm. Calculate the expected absorbance of solution of Red No. 3 with a concentration of 4.00×10–6M when measured at 629 nm in a 2.00 cm cell.arrow_forward
- Chemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning