Download CHEM 122: Introduction to Organic Chemistry Chapter 1: Organic

CHEM 122: Introduction to Organic Chemistry
Chapter 1: Organic Chemistry.
1. Write Lewis structures for these compounds. Show all valence electrons. None
of them contains a ring of atoms. (Hint: Remember that carbon has four bonds,
nitrogen has three bonds and one unshared pair of electrons, oxygen has two
bonds and two unshared pairs of electrons, and each halogen has one bond and
three unshared pairs of electrons.)
a)
b)
c)
d)
e)
f)
H2O2
N2H4
CH3OH
CH3SH
CH3NH2
CH3Cl
Hydrogen peroxide
Hydrazine
Methanol
Methanethiol
Methylamine
Chloromethane
2. Write Lewis structures for these compounds. Show all valence electrons. None
of them contains a ring of atoms.
a)
b)
c)
d)
e)
f)
g)
h)
CH3OCH3
C2H6
C2H4
C2H2
CO2
CH2O
H2CO3
CH3COOH
Dimethyl ether
Ethane
Ethylene
Acetylene
Carbon dioxide
Formaldehyde
Carbonic acid
Acetic acid
3. Write Lewis structures for these ions.
a)
b)
c)
d)
HCO3CO32CH3COOCl-
Bicarbonate ion
Carbonate ion
Acetate ion
Chloride ion
4. Why are the following molecular formulas impossible?
a) CH5
b) C2H7
5. Use the VSEPR model to predict the bond angles and geometry about each circled
atom. (Hint: Remember to take into account the presence of unshared pairs of
electrons.)
H
H
H
C
C
H
H
H
O
H
H
a)
C
C
H
H
Cl
H
C
C
C
H
H
b)
c)
6. Use the VSEPR model to predict the bond angles and geometry about each circled
atom.
H
H
O
H
C
O
H
a)
C
N
H
H
H
H
b)
O
N
O
c)
7. Draw Lewis structures for each of the following functional groups. Show all
valence electrons in each functional group.
a)
b)
c)
d)
e)
An aldehyde group
A carboxylic acid group
A hydroxyl group
A primary amino group
An ester group
8. Complete the following structural formulas by adding enough hydrogens to
complete the tetravalence of each carbon. Then write the molecular formulas of
each compound.
O
C
C
C
C
C
C
C
a)
C
C
C
H
C
C
C
C
NH2
C
C
C
C
C
h)
C
C
OH
C
OH
NH2
f)
OH
C
C
O
e)
OH
C
c)
C
d)
g)
C
C
OH
C
C
C
C
b)
O
C
C
C
O
O
C
C
OH
C
i)
C
9. Draw a structural formula for the one tertiary (3 o) alcohol with the molecular
formula C4H10O.
10. Draw condensed structural formulas for all compounds with the molecular
formula C4H8O that contain a carbonyl group (there are two aldehydes and one
ketone).
11. Draw structural formulas for the six ketones with the molecular formula C 6H12O.
12. Draw structural formulas for each of the following:
a) The four primary (1o) amines with the molecular formula C4H11N
b) The three secondary (2o) amines with the molecular formula C4H11N
c) The one tertiary (3o) amine with the molecular formula C4H11N
13. Silicon is immediately below carbon in Group 4A of the Periodic Table. Predict
the C—Si—C bond angles in tetramethylsilane, (CH3)4Si.
14. Draw the structure for a compound with the molecular formula
a)
b)
c)
d)
C2H6O that is an alcohol
C3H6O that is an aldehyde
C3H6O that is a ketone
C3H6O2 that is a carboxylic acid
15. Identify the functional group(s) in each compound
O
O
CH3CH2CCH3
2-butanone
(a solvent for paints and lacquers)
a)
O
H2NCH2CH2CH2CH2CHCOH
Lysine
NH2
(one of the 20 amino acid
building blocks of proteins)
c)
O
HOCCH2CH2CH2CH2COH
Hexanedioic acid
(the 2nd component of nylon-66)
b)
O
HOCH2CCH2OH
Dihydroxyacetone
(a component of several
artificial tanning lotions)
d)
16. Consider molecules with the molecular formula C4H8O2. Write the structural
formula for a molecule with this molecular formula that contains
a)
b)
c)
d)
A carboxylic acid group
An ester group
A ketone group and a 2o alcohol group
An aldehyde and a 3o alcohol group
17. Urea, (NH2)2CO, is used in plastics and in fertilizers. It is also the primary
nitrogen-containing substance excreted by humans.
O
H
C
H
N
N
H
H
Urea
a)
b)
c)
d)
Complete the Lewis structure of urea, showing all valence electrons.
Predict the bond angle about each C and N.
Which is the most polar bond in the molecule?
Is urea polar or nonpolar?