DECEMBER 20, 2002Name:____________________________Student ID No:____________________Critical Values for the Rejection Quotient QValues of t for Various Levels of ProbabilityCHEMISTRY 226 FINAL EXAM DECEMBER 20, 2002 Name:____________________________ Student ID No:____________________ I. (2 pts each) Match the following terms and definitions. 1. ______ Measure of chromatographic columns ability to separate two analytes. 2. ______ Spontaneous electrochemical cell. 3. ______ Electrode at which oxidation takes place. 4. ______ Gain of electrons. 5. ______ Type of chromatography in which the stationary phase is non-polar and the mobile phase is polar. 6. ______ Delayed emission of photons is measured following absorption. 7. _______ Term used to describe chromatographic column efficiency. 8. ______ Closeness of measured value to accepted value. 9. ______ Process by which a coagulated colloid returns to its dispersed state. 10. ______ pKa ± 1 A. Accuracy J. Oxidation B. Anode K. Peptization C. Cathode L. Phosphorescence D. Digestion M. Plate Height E. Electrolytic Cell N. Precision F. Fluorescence O. Reduction G. Galvanic Cell P. Resolution H. Indicator pH range Q. Reversed Phase Chromatography I. Normal Phase Chromatography II. (3 pts). EDTA has six binding sites. Name them.III. For the following cell: Zn│Zn2+ (0.0364 M) ║ Tl3+ (9.06 X 10-3 M), Tl+ (0.0620 M)│ Pt 1. (2 pts) Write each half reaction as a reduction. 2. (5 pts) Calculate the theoretical potential of the cell. 3. (3 pts) Calculate the change in free energy. IV. For a wavelength of 3000 nm calculate: 1. (3 pts) the frequency in Hz 2. (3 pts) the energy in Joules.V. (5 pts) Calculate the potential of a platinum electrode immersed in a solution that is 0.0750 M Sn(SO4)2 and 2.5 X 10-3M SnSO4. VI. A solution containing the complex formed between Bi (III) and thiourea has a molar absorptivity = 9.32 X 103. 1. (5 pts) Calculate the absorbance of a 6.24 X 10-5 M solution at 470 nm in a 2.50 cm cell. 2. (2 pts) Calculate the % transmittance. VII. (7 pts) A 5.00 g sample of pesticide (DDT; C14H9Cl5; 354.5 g/mol) was decomposed with metallic sodium in alcohol and the liberated chloride ion precipitated as AgCl (143.3 g/mol). Calculate the %DDT in the original sample based on recovery of 0.1606 g AgCl.VIII. Consider the following set of data. Show all calculations. Trial Number Weight (g) 1 0.624 2 0.613 3 0.596 4 0.607 5 0.582 1. (3 pts) Calculate the 95% confidence limit if s → σ = 0.015. 2. (3 pts) If the accepted value is 0.625 g calculate the relative error of the mean. 3. (5 pts) Use the appropriate statistical test to determine if the 0.582 value is an outlier at the 95% confidence limit. IX. (7 pts) The homogeneity of a batch of chloride standards was tested by analyzing samples taken randomly from two bottles. The following results were obtained. Bottle 1 (% Chloride) Bottle 2 (% Chloride) 26.32 26.28 26.33 26.25 26.38 26.38 26.39 Is there a significant difference between the two bottles at the 95% confidence limit if the pooled standard deviation = 0.51%?X. 1. (4 pts) Calculate the solubility product constant for a 4.7 X 10-6 M Ag3PO4 solution. 2. (3 pts) Calculate the solubility of the solution if the F concentration = 0.05M. XI. (5 pts) Draw a block diagram of a fluorescence instrument. XII. (4 pts) Describe two reasons for deviations from Beer’s Law.Answer ONE of the following two questions. Clearly mark the question you want graded. XIII. (8 pts) (Use activities to calculate the solubility of Mg(OH)2 (Ksp)= 7.1 X 10-12) in a 0.0167 M Ba(NO3)2 solution. XIV. (8 pts) What is the pH of a solution prepared by dissolving 9.20 g lactic acid (90.08 g/mol) and 11.15 g sodium lactate (112.06 g/mol) and diluting to 1L? Ka = 1.38 X 10-4. (DO NOT USE APPROXIMATIONS)Critical Values for the Rejection Quotient Q Confidence Levels of Various Values of z. Confidence Levels % z 50 0.67 68 1.00 80 1.29 90 1.64 95 1.96 95.4 2.00 99 2.58 99.7 3.00 99.9 3.29 # Observations 90% Confidence 95% Confidence 99% Confidence 3 0.941 0.970 0.994 4 0.765 0.829 0.926 5 0.642 0.710 0.821 6 0.560 0.625 0.740 7 0.507 0.568 0.680 Values of t for Various Levels of Probability Degrees of Freedom 90% CI 95%CI 99%CI 1 6.31 12.7 63.7 2 2.92 4.30 9.92 3 2.35 3.18 5.84 4 2.13 2.78 4.60 5 2.02 2.57 4.03 6 1.94 2.45 3.71 7 1.90 2.36 3.50 8 1.86 2.31 3.36 9 1.83 2.26 3.25 10 1.81 2.23 3.17 Standard Electrode Potentials Thallium E0 Tin E0 Tl+ + e- Tl(s) -0.336 Sn2+ + 2e- Sn(s) -0.136 Tl3+ + 2e- Tl+ +1.25 Sn4+ + 2e- Sn2+ +0.154 Zinc Zn2+ + 2e- Zn(s)