Question 1 [40 marks] (a) Two homogeneous (.e. soluble) Fe complexes are dissolved in solution. Both...

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Question 1 [40 marks] (a) Two homogeneous (.e. soluble) Fe complexes are dissolved in solution. Both complexes are present at a concentration of 0.004 M each. Complex 1 exhibited an absorption band with a max value of 320, an Absorbance maximum of 0.8, and a Full Width Half Maximum value of 40 nm. Complex 2 exhibited an absorption: band with a with Junx of 375, an Absorbance maximum of 0.60, and a Full Width Half Maximum value of 25 nm. (i) What is the energy of the electronic transitions that results in the absorption band observed for Complex 1 and Complex 2? [4 marks] (ii) Based on the information provided, how much larger is the molar absorption coefficient of Complex 1 than Complex 2. [6 marks] (ii) Estimate the absorbance value exhibited by Complex 2 at a concentration of 0.045 M, assuming all other parameters remain unchanged. [2 marks] (b) The two Fe complexes dissolved into the solution described in Question 1(a) are then studied by Raman spectroscopy. When the Raman spectra of Complex 1 and Complex 2 are recorded, they each display one vibrational band that can be attributed to an Fe-OH hydroxide unit. The Raman band is detected at 615 cm-1 for Complex 1, and at 525 cm for Complex 2. Both Raman bands are of equal intensity using an incident laser wavelength of 514 nm. (i) If the Fe-OH unit present in Complex 1 and in Complex 2 is a simple harmonic oscillator, and that the force constant, k, is unchanged, calculate the Raman shift value (in wavenumbers) expected for both Fe-OH units, after you isotopically substitute "O with "O via treatment in HO". (c) [Ar(Fe) = 55.8; Ar(0) = 16; Ar(150) = 18] [12 marks] (i) Assuming the vibrational bands of the Fe-OH hydroxide unit in both soluble Fe complexes possess the correct symmetry to undergo resonance 2 enhancement, would expect the intensity of the Raman bands of Complex 1 to be more, or less, intense than the Raman bands of Complex 2, if the incident laser wavelength is changed from 514 nm to 325 nm? [2 mark] (iii) Explain your answer to Question 1 (b) (ii) by reference to suitable schematics and equations. [6 marks] You have been asked by your project manager to determine some physical properties of a thin film solar cell, that is used for photovoltaic applications. (i) If you wanted to determine the surface properties of your material, explain whether you would use X-Ray Photoelectron spectroscopy (XPS) or X-Ray diffraction (XRD) as your primary analysis method. [4 marks] (d) Suggest and justify a suitable ionisation strategy to determine the following information by Mass Spectrometry: (i) The molecular weight of a disaccharide, which is primarily composed of 2 glucose (CHO) units that are bonded together. (II) The quantity of metal impurities in an inorganic mineral. [4 marks] Question 1 [40 marks] (a) Two homogeneous (.e. soluble) Fe complexes are dissolved in solution. Both complexes are present at a concentration of 0.004 M each. Complex 1 exhibited an absorption band with a max value of 320, an Absorbance maximum of 0.8, and a Full Width Half Maximum value of 40 nm. Complex 2 exhibited an absorption: band with a with Junx of 375, an Absorbance maximum of 0.60, and a Full Width Half Maximum value of 25 nm. (i) What is the energy of the electronic transitions that results in the absorption band observed for Complex 1 and Complex 2? [4 marks] (ii) Based on the information provided, how much larger is the molar absorption coefficient of Complex 1 than Complex 2. [6 marks] (ii) Estimate the absorbance value exhibited by Complex 2 at a concentration of 0.045 M, assuming all other parameters remain unchanged. [2 marks] (b) The two Fe complexes dissolved into the solution described in Question 1(a) are then studied by Raman spectroscopy. When the Raman spectra of Complex 1 and Complex 2 are recorded, they each display one vibrational band that can be attributed to an Fe-OH hydroxide unit. The Raman band is detected at 615 cm-1 for Complex 1, and at 525 cm for Complex 2. Both Raman bands are of equal intensity using an incident laser wavelength of 514 nm. (i) If the Fe-OH unit present in Complex 1 and in Complex 2 is a simple harmonic oscillator, and that the force constant, k, is unchanged, calculate the Raman shift value (in wavenumbers) expected for both Fe-OH units, after you isotopically substitute "O with "O via treatment in HO". (c) [Ar(Fe) = 55.8; Ar(0) = 16; Ar(150) = 18] [12 marks] (i) Assuming the vibrational bands of the Fe-OH hydroxide unit in both soluble Fe complexes possess the correct symmetry to undergo resonance 2 enhancement, would expect the intensity of the Raman bands of Complex 1 to be more, or less, intense than the Raman bands of Complex 2, if the incident laser wavelength is changed from 514 nm to 325 nm? [2 mark] (iii) Explain your answer to Question 1 (b) (ii) by reference to suitable schematics and equations. [6 marks] You have been asked by your project manager to determine some physical properties of a thin film solar cell, that is used for photovoltaic applications. (i) If you wanted to determine the surface properties of your material, explain whether you would use X-Ray Photoelectron spectroscopy (XPS) or X-Ray diffraction (XRD) as your primary analysis method. [4 marks] (d) Suggest and justify a suitable ionisation strategy to determine the following information by Mass Spectrometry: (i) The molecular weight of a disaccharide, which is primarily composed of 2 glucose (CHO) units that are bonded together. (II) The quantity of metal impurities in an inorganic mineral. [4 marks]

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a i The energy of the electronic transitions can be calculated using the formula E hc where E is the energy h is Plancks constant c is the speed of li... View the full answer