Quantitative Analytical Chemistry
1. To convert between natural logarithm (ln) to base 10 logarithm, times by 2.303. So what is the expected slope in the Nernst equation (n=1) if your temperature was 15.17 and not 25.00 degrees celsius?
2. What is the electromotive efficiency, ß, if your temperature is 36.85 degrees Celsius and your slope is 0.05916 (n=1) in the Nernst equation?
3. When Dr. Harris was a boy, Uncle Wilbur let me watch as he analyzed the iron content of runoff from his banana ranch. A 5.00 mL sample was acidified with nitric acid and treated with excess KSCN to form a red complex. (KSCN is colorless). The solution was then diluted to 25.00 mL and put in a variable pathlength cell. For comparison, a 10.0 mL reference sample of 7.62 x 10-4 M Fe3+ was treated with HNO3 and KSCN and diluted to 25.00 mL. This reference sample was placed in a 1.00 cm light path. The runoff sample exhibited the same absorbance as the reference when the path length of the runoff cell was 4.08 cm. What was the concentration of iron in ppm Fe (not M) in Uncle Wilbur's runoff?