Chem 155 W08
Chem 155 Homework #9 Due at the start of class on Mon. March 10
Reading: Finish Chapter 16, begin Chapter 17 (note—you should try to read ALL of chapter 17
before the last day of lecture on March 16).
Chapter 15 Problems: DeBroglie turned over in his grave after the midterm!
15.31
Chapter 16 Problems:
16.5
16.8
16.10
16.12
16.16
16.17
16.18
16.22
16.28
16.39
Chapter 17 Problems:
17.1
17.2
17.13
17.15
Additional Problems:
1) When we breath in air, O
2
is taken up in the blood by the protein hemoglobin, which contains
Fe
2+
ions bound to a heme group [(heme)Fe
2+
]. The iron-heme reversibly binds O
2
, picking it up
and releasing it in the other tissues (see Oxtoby, pp. 284-286). In the bound form (oxygenated
heme), one electron is transferred from the iron to the O
2
so that this species can be described as
[(heme)Fe
3+
(O
2-
)]. Is the oxygen-oxygen bond length in heme longer or shorter than the bond in
O
2
. Explain.
2) A quantum cascade laser is a laser that emits light when electrons make transitions between
levels in artificial quantum wells grown in a semiconductor chip. Treat the energies as a 1D
‘particle-in-an-infinite-box’ problem and assume the laser action occurs between the n=3 and
n=2 levels in wells that are 2.5 nm wide. What wavelength of light is emitted? What part of the
spectral region is this? Suggest how a chemist might use such a laser to make a measurement.
3) Discuss the experimental evidence supporting the existence of molecular orbitals. Explain
how a chemist might measure the energy of an electron in a particular molecular orbital.