1. What is the wavelength of an emission line for iron that has a frequency of 5.68×1014 Hz? 2. A solution of CoL3+ has a percent transmittance of 28.9 % at 565 nm in a 2.00 cm cell. The molar absorptivity for the complex at this wavelength is 2.45×104 L/(mol•cm). What is the absorbance of CoL3+ in this solution? 3. A ...continues
Molar Absorptivity and Beer's Law
4. A weak organic acid in its dissociated form (A-) absorbs at 375 nm with a molar absorptivity, ε, of 4.48×103 L/(mol•cm). The non-dissociated form of the acid (HA) does not absorb at 375 nm. At 375 nm, a 3.0×10-3 M solution of the acid in water has an absorbance of 0.462 in a 1.00 cm cell. a. What is the concentratio ...continues
Spectrophotometry and Chromatographic Separations
1) When measured in a 1.00 cm cuvet, a 9.45×10-4 M solution of species A exhibited absorbances of 0.155 and 0.687 at 450 nm and 725 nm, respectively. A 2.65×10-3 M solution of species B gave absorbances of 0.613 and 0.078 at 450 nm and 725 nm, respectively. Both species were dissolved in the same solvent, and the solvent’s absor ...continues
Concentrations of Hexanol and Pentanol from a Chromatogram
3) Solution 1 contains a ratio of 2.54 :1 pentanol to hexanol. When the chromatogram was run, the peak area of the pentanol was found to be 4,320, and the peak area of the hexanol was found to be 4,156. When an unknown was run, a solution containing 1.00 mL of the unknown pentanol was mixed with 5 mL of 1.42 mM hexanol, and the ...continues
Quantitative Analysis : Uncertainty, Significant Figure and Energy Diagrams
Find the absolute uncertainty of the following calculations and express the answer with the proper number of significant figures. a) 2.0394 (± 0.0008) + 3.256 (± 0.004) - 1.17 (± 0.01) = ______________________________ b) 91.3 (± 0.5) * 40.03 (± 0.02) / 16.1 (± 0.3) = _____________________________________ c) [12.34 (± 0.04) ...continues
Electrochemistry and the Nernst Equation
1.Consider the following cell at equilibrium: Mg(s) / Mg+2 (0.01 M) // OH- (?) / Mg(OH)2 (s) / Mg (s) Given: Mg+2 + 2e- ---> Mg(s) Eo = -2.360 V Mg(OH)2 (s) + 2e- ---> Mg(s) + 2 OH- Eo = -2.690 V a) Write each half-reaction and the net cell reaction. Find the standard net cell potential. b) Find the pH of the right cel ...continues
Quantitative Analysis : HPLC Chromatographs and Beer's Law
Please see the attached file for the fully formatted problems. 1.Based on the following figure explain which particle size produce the best resolution in HPLC and why? 2. To find the Ce4+ content in a solid, 4.37 g were dissolved and treated with and excess of iodate to precipitate Ce(IO3)4. The precipitate was filtered, w ...continues
Spectrophotometry, Absorbance and Transmittance
1.A portable photometer with a linear response to radiation registered 73.6 μA with a blank solution in the light path. Replacement of the blank with an absorbing solution yielded a response of 24.9 μA. Calculate: a) The percent transmittance of the sample solution. b) The absorbance of the sample solution. ...continues
Solubility and Concentration of Ions
What is the pCl- value for a solution that is 0.040 M KCl and 0.020 M in MgCl2? a) 0.6 b) 1.1 c) 1.2 d) 1.4 e) 1.7 II) The 90% confidence limits for ppm magnesium in a sample are 3.56±0.32 ppm Mg. This indicates that the interval of 3.24 ppm Mg to 3.88 ppm Mg a) has a 90 % chance of enclosing the true ...continues
Quantitative Analysis and Electrochemistry
IX) Given the following information, which of the statements is true? Cu2+(aq) + e- → Cu+(aq) Eº = 0.34V 2 H+(aq) + 2 e- → H2(g) Eº = 0.0V Fe2+(aq) + 2 e- → Fe(s) Eº = - 0.44V Ni(s) → Ni2+(aq) + 2 e- Eº = 0.25V a) Cu+2(aq) is the strongest oxidizing agent b) Cu+2(aq) is the weakest oxidizi ...continues
