CHEMISTRY 133
Spring, 2015 Homework Set 2
Only Problems in Bold are Submitted for Grading
Set 2.1 - Complete for quiz on Mar. 12
Harris Text: Ch. 13: 16, 19, 28, 36; Ch. 14: 2, 20; Ch. 17: 3, 4
Additional Problems:
1. Calculate the potential for the cell describe bellow when [ZnSO4] = 2.0 x 10-3 M
Zn(s)|ZnSO4(aq)|PbSO4(s)|Pb(s). Look up standard reduction potentials in Appendix H.
Set 2.2 - Complete for quiz on April 2
Harris Text: Ch. 17: 11, 16, 24, Ch. 19: 1, 3-6, 10, 11, 13, 28
Additional Problems:
1. The transmittance of a dye is measured at 524 nm using a 1 cm cell in five samples. At this wavelength, the dye is known to have a molar absorbtivity of 63,200 M-1 cm-1. Given the transmittance values in the table below, and assuming that the uncertainty on each transmittance measurement is a constant value of 0.008, calculate the concentration of each dye sample and its uncertainty. You may want to consult Harris Appendix C which covers propagation of uncertainty in such cases.
Dye Sample # |
Transmittance (not given as a %) |
1 |
0.092 |
2 |
0.131 |
3 |
0.489 |
4 |
0.864 |
5 |
0.913 |
Solutions Notes: I did one part of the propagation of error calculation, related to the above additional problem, incorrectly on the board - see below for correction
A = -logT = ebC or C = -logT/eb = -lnT/2.303eb (incorrectly written on the board as -eblnT/2.303)
With this change, sC = sT/(eblT2.303) (see solutions for more details)
Set 2.3 - Complete for exam 2 on April 9
Ch. 20, 1, 2, 4, 7, 14, 21
No additional Questions