# HW_5 - -; E = +0.5345 V. 3. A 3.6 g soil sample was treated...

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CHEM 150 HOMEWORK #5 Due: Thursday, 7/17/08 1. A sample of toothpaste was analyzed for its fluoride content by treating a 250 mg sample with an ionic strength buffer to extract F - followed by dilution to 100.0 mL. The potential reading with a fluoride ISE was +150.3 mV. After addition of 10.0 mL of a 50.0 ppm F - standard, the potential reading became +110.8 mV. Assuming a slope of –58.0 mV for the fluoride ISE, calculate the fluoride content of the toothpaste in %NaF. 2. The following cell was employed to determine [I - ] Cd(s)|Cd 2+ (0.100M)||I - (xM), I 2 (sat’d)|Pt(s). Deteremine [I - ] if the cell potential is +1.063 V. The standard potentials are: Cd 2+ + 2e - = Cd(s); E° = -0.403 V and I 2 + 2e - = 2I
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Unformatted text preview: -; E = +0.5345 V. 3. A 3.6 g soil sample was treated with HClO 4 and HF was distilled from the mixture. The HF distillate was then diluted to a volume of 50.0 mL. Measurement with a fluoride ISE resulted in a potential of +95 mV. Exactly 5.00 mL of 1 x 10-3 M F-standard was added to the 50.0 mL solution and the potential on the fluoride ISE became +68 mV. Calculate the fluoride content in the soil as %F-. 4. The following cell was employed to determine pCrO 4 SCE||Ag 2 CrO 4 (satd), CrO 4 2-(aq)|Ag(s). Deteremine pCrO 4 if the cell potential is +0.476 V. The standard potential for Ag + + e-= Ag(s) is E = +0.799 V (use E SCE = +0.241 V for the anode voltage)....
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## This note was uploaded on 08/06/2008 for the course CHEM 150 taught by Professor Buratto during the Summer '08 term at UCSB.

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