Chemistry Exercise

CHEM 111Homework – Ch. 9
due as Canvas upload Wed 11/23
Name _______________________________________
Questions are worth 4 points each.
1. For each of the following compounds: (a) draw a full Lewis structure; (b) indicate the hybridization
of each carbon atom; (c) identify the approximate bond angle around the carbon.
a. CO32–
b. NCO–
2. For each of the following compounds: (a) draw a full Lewis structure; (b) indicate the hybridization
of each bromine atom; (c) identify the approximate bond angle around the bromine.
a. BrF3
b. BrF5
3. Use a molecular orbital diagram such as those shown in Fig. 9.16 and Table 9.1 to place C2–, C2, and
C2+ in order of: (a) increasing bond energy; (b) increasing bond length.
4. In each of the following equations, what hybridization change, if any, occurs for the underlined atom?
a.
b.
c.
d.
BF3 + NaF ® NaBF4
PCl3 + Cl2 ® PCl5
SiF4 + 2F– ® SiF62–
SO2 + ½ O2 ® SO3
5. (Challenge question) Tryptophan is one of the amino acids found in proteins, and is a biochemical
precursor to serotonin, the neurotransmitter responsible for feelings of relaxation and happiness.
Turkey has a high level of tryptophan and this is often blamed for the drowsy feeling you get after
eating your Thanksgiving dinner.* The structure of tryptophan is shown below.
H
1
H
H
H
H
C
C
C
H
b
C
C
4
C
C
H
2
Ca
H
C
O
3
H
O
C
6
C
H
Nc
H
5
N
H
a. What is the hybridization of each of the numbered C, N, and O atoms?
b. How many s bonds are present in tryptophan? How many p bonds?
c. Predict the bond angles at points a, b, and c.
*
This is not true! The real reason we get tired after Thanksgiving dinner is that we usually eat too much and the digestion process
takes all of our energy.