Redox Titrations
Find the half-cell potential for a solution that contains 0.50 M Cl- at equilibrium given that the equation involved is AgCl(s) + e- <--> Ag(s) + Cl-, E0 = 0.222 V.
0.240 V
What is a typical fuel/oxidant mix for an atomic absorption premix burner?
Air and acetylene.
What is an analytical separation?
A process that separates a complex mixture into its individual components.
What is gas chromatography's mobile phase?
Gas.
Calculate E0 and K for the following reaction:
2F2 (g) + H2O <--> F2O(g) + H+ + 2F-
E0 = 0.722 V
K = 7 x 1048
What part of the apparatus converts the metal ions in solution into metal atoms?
Is chromatography a type of analytical separation?
Yes.
How can the variable A in the Van Deemter equation be decreased to decrease band broadening in packed columns?
What is a combination electrode?
An electrode that includes both a working and a reference electrode.
What type of flame would be used for samples that form oxides easily?
A fuel rich flame (reddish).
Should the number of theoretical plates be higher or lower for a more efficient chromatography process?
Higher.
In a redox titration, how is the equivalence point detected?
Either by detecting a voltage change with an electrode or by a color change in a colorimetric indicator.
When doing a titration, temperature should...
What type of interference can be corrected by running a blank?
Background absorption.
What are some causes of band broadening, and what equation relates these factors?
Multiple pathways through column packing (A), diffusion (B), and mass transfer between phases (C); Van Deemter equation.
What is sodium error? How does this affect the pH measurement?
A type of pH measurement error that occurs when there is an excess of sodium ions and a small amount of H+ in solution. The pH reads lower than the true value.
100.00 mL of 0.256 N K2Cr2O7 is titrated with 15.46 mL of 0.6781 N Fe3+. Find the potential at the cathode. Assume the total solution volume after additions is 235 mL and hydronium concentration is 1.0 x 10-3 M.
0.96 V
What type of absorption issue can be corrected by adding a releasing agent?
Chemical error.
What should N (number of theoretical plates), H (height of theoretical plates), and α (selectivity factor) be for a good separation?
N should be large, H should be small, and α should be large.
What equation is used to determine potential at non-standard conditions?
The Nernst equation.