**CHEMISTRY 133**

**Spring, 2015 Homework Set 2**

**Only Problems in Bold are Submitted for Grading**

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**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 [ZnSO _{4}] = 2.0 x 10^{-3} M**

**Zn(s)|ZnSO _{4}(aq)|PbSO_{4}(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

Text Solutions

**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