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:
Trending nowThis is a popular solution!
Chapter 12 Solutions
Principles of Instrumental Analysis
- The first excited state of Cu is reached by absorption of 327-nm radiation. (a) What is the energy difference (J) between the ground and excited states? (b) The ratio of degeneracies is g*/g0 3 for Cu. Find N*/N0 at 2 400 K. (c) By what percentage will the fraction in (b) be changed by a 15-K rise in temperature? (d) What will the ratio N*/N0 be at 6 000 K?arrow_forwardThe reaction 9Be (3H, p) 11Be is studied by bombarding 9Be with 5 MeV tritons.Protons with energies of 2.260, 1.967 and 0.620 MeV are observed at 90 ° of the incident beam due to the formation of 11Be in the ground state and in two excited states:(a) Find the atomic mass of 11Be.(b) Find the excitation energy of the excited states.arrow_forwardNote: The Emission Intensity of the original solution is not given since the calibration method is standard addition.arrow_forward
- Calculate 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_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_forwardCovalent 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_forward
- The 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_forwardWhich of the two instrumental modes, atomic absorption or atomic emission, results inthe better detection of metal ions in general? Describe the processes that an analyte solution goes through during atomization in the graphite furnace.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
- 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_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