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
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- 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_forwardCalculate the molar absorptivity and absorbance of a 1.00 x 104 M solution, which has atransmittance of 32.1% , when the path length is 2.5 cm at 650 nm. (arrow_forwardPhotobromination 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
- Absorbance 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_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_forwardA student wanted to determine the level of lead in amoxicillin powder, so he transferred 148 mg of the powder to 200 ml volumetric flask and completed the volume volumetrically, then he transferred 5 ml of the obtained solution to 50 ml volumetric flask and completed the volume properly, and read the absorbance of the obtained solution on AAS. The reading was 0.48. and the calibration equation was: "Y =12.25 x- 0.05" (concentration microg./mL). ?"Calculate the content of lead in amoxicillin as "ppm 326.5.a O 605.0 .b O 60.5.c O 17.5.d O 584.7.e O أخل اختياريarrow_forward
- 4. (Part A When ultraviolet radiation of wavelength 400nm passes through 2.50 mm of a solution of an absorbing substance at a concentration 0.717 mmol/dm?, the transmission is 61.5%. Calculate the molar absorption coefficient of the solute at this wavelength. (Part B A molecular absorption transition has a molar absorption coefficient (extinction coefficient) of 60,220 dm/mole cm. What is the absorption cross-section in cm?/molecule?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_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
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