Electrochemistry Homework Problem Set #3
This problem set was developed by S.E. Van Bramer for Chemistry 366 at Widener University.
Questions are based on Skoog, West & Holler An Introduction to Analytical Chemistry. Some questions and data are based upon information from this textbook.
- (3 pts) Compare and contrast the instrument settings, the sensitivity, and the signal for the following electrochemical techniques.
- Linear-scan vs normal pulse voltammetry
- Normal pulse vs differential pulse voltammetry
- Differential pulse vs square wave voltammetry
- Anodic stripping voltammetry vs voltammetry
- (3 pts) What would you do if....
- You are running a differential pulse experiment with pulse width of 1 ms and a pulse height of 100 mV and a glassy carbon electrode. What would you do to increase the S/N.
- You are running a differential pulse experiment with pulse width of 1 ms and a pulse height of 100 mV and a glassy carbon electrode. What would you do to improve the resolution.
- You are running a normal pulse experiment with pulse width of 20 ms and a glassy carbon electrode. What would you do to improve the resolution.
- You are running a square wave experiment with a 1 kHz pulse frequency and a dropping mercury electrode. What would you do to significantly reduce the limit of detection.
- (4 pts) An unknown sample was analyzed by differential pulse voltammetry with a DME. Samples were prepared by pipetting (with Class A pipetts) the volumes indicated and diluting to a total volume of 50.00 mL in a Class A volumetric flask. The following samples were prepared and analyzed. Calculate the concentration of lead in the original sample. Use propagation of error to determine the uncertainty in the concentration.
|Sample (mL)||KCl (mL) 0.400 M||Pb2+ (mL) 12.4 ppm||Current (uA)|
Please send comments or suggestions to firstname.lastname@example.org
Scott Van Bramer
Department of Chemistry
Chester, PA 19013
© copyright 1996, S.E. Van Bramer
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Last Updated: 1/9/2003