Chemistry 217
Problem Set 1
Recommended Problems from the Book (1st ed. in parentheses): 1.1, 1.3-1.9, 1.36-1.42,
1.57-1.62 (1.1-1.8, 1.34-1.40, 1.54-1.58)
Supplemental Problems: Lewis structures: Weeks, pp. 1-14. Formal Charge: Weeks,
pp. 20-25; Klein, section 1.5. Lone pairs: Klein, section 1.6. Skeletal structures
(condensed structures): Klein, section 1.1-1.4.
1.
Draw the Lewis structure for each of the following molecules. Show all lone
pairs. All molecules are neutral and all formal charges are zero.
(a)
CH2Cl2
(d)
CH3CH2CO2CH3
2.
Each of the following molecules is neutral. Determine the formal charge for each
atom in the molecules (All lone pairs are shown).
(b)
(CH3)3COH
(c)
(CH3)2O (same as CH3OCH3)
(e)
(f)
CH3CH(CH2CH3)CH2NHCH3
(a)
C
C
(b)
O
(d)
3.
O
C
O
P
H
CH3
H
CH3
C
CH3
(c)
P
H
CH3
H3C
CH3
(e)
(h)
C
H2C
N
O
C
O
H2C
N
N
(f)
N
(i)
Fill in the lone pairs on the following molecules. All non-zero formal charges are
shown.
N
(a)
(b)
O
H3C
(d)
CH3
CH3
O
H3N
(g)
CH3
H
H
H
CH3CHO
H3C
Si
H
O
Cl
CH3
(c)
N
(d)
H
(e)
H
C
H
4.
In class, we determined the rules of thumb in determining formal charge for
carbon. This information is shown in the first rows of the table below. Fill in the
remaining blank spaces for H, O, and N. Remember that you cannot violate the octet
rule.
Atom
C
# of bonds
4
3
3
# of lone pairs
0
0
1
charge
0
+1
-1
0
+1
-1
0
+1
-1
0
+1
-1
H
O
N
5.
Fill in the lone pairs and formal charges on the atoms in the following molecules
(all hydrogens are shown).
F
B
(a)
O
F
(b)
F
HO
H
(c)
H
O
H
H
(e)
H
H3C
F
F
(d)
O
(f)
H
H
O
O
CH3
H
O
O
(g)
H
(h)
O
S
O
O
(i)
N
N
N
6.
Draw valid Lewis structures for the following. For each one, assign all non-zero
formal charges and the overall charge on the molecule.
(a)
H3NCH2CHNH
(b) CH3CH2CO2
(c) CH2CHCH2
(7)
Draw constitutional isomers which fulfill the following criteria:
(a)
(b)
(c)
(d)
(e)
(8)
Pentane: C5H12 (three different isomers)
C4H10O
C5H10 (Draw at least four. Two should be cyclic molecules. Two should
contain a carbon-carbon double bond.
C6H10 (Draw at least one isomer of compounds containing the following
types of functionality: 1) a compound with two double bonds; 2) a
compound with a ring and a double bond; 3) a compound with a triple
bond; 4) a compound with two rings
C5H10O2 (Draw as many as you can.)
Give the molecular formula of the following compounds:
HO
O
HO
N
O
N
HO
(a)
nicotine
(b)
HO
OH
vitamin C
(c)
cholesterol