Question 5: Two-part question: The accuracy of a spectrophot…

Question 5: Two-part question: The accuracy of a spectrophotometer is evaluated by preparing a solution of 15.50 mg/L K2Cr2O7 (molar mass 294.18 g/mol) in 0.0050 M H2SO4, and measuring its absorbance at a wavelength of 575 nm in a cell with a path length of 1.00 cm. The measured transmittance is 0.576. a) What is the expected molar absorptivity of K2Cr2O7 at this wavelength? (Hint: Use Beer law)           (8 points)   b) What is the energy in Joule of the electronic transition resulting from the absorption at 575 nm?(c = 3.00 *108 m s-1; h = 6.63 *10-34 J s)  (3 points)

Question 9: Refer to the following shorthand description of…

Question 9: Refer to the following shorthand description of an electrochemical cell to answer questions a-c: SHE || Fe3+ (aFe3+ = 0.032), Fe2+ (aFe2+ = 0.090) | Pt a) What is the potential of the complete electrochemical cell? (8 pts)   b) If this full cell is allowed to operate as a galvanic (voltaic) cell (i.e., a discharging battery), which half-cell is acting as the anode? (2 pts)   c) What is the potential of the cathode relative to a Ag/AgCl electrode (use the standard electrode potential for this reference electrode given at the end of your exam)? (5 pts)