Organic3.doc
____
1. The correct IUPAC name of the compound
____
a. 3,4-dimethylpentane
b. 2,3-dimethylbutane
2. Name the cycloalkane given below.
____
a. 1,2,4-trimethylcyclohexane
c. 1,2,4-trimethylcyclopentane
b. 1,2,4-dimethylcyclopentane
d. 1,3,5-trimethylcyclopentane
3. The correct structural formula of 1,2-diethyl-2,3-dimethyl-6-propylcyclooctane is ____.
a.
b.
c.
d.
____
is ____.
c. 2,3-dimethylpentane
d. 2,2,3-dimethylbutane
4. The correct condensed structure of a compound having the IUPAC name 6-ethyl-6,7-dimethyl-2,4-dioctyne is
____.
a.
b.
c.
d.
____
____
5. Which is NOT an isomer of hexane?
a. 2-methylpentane
c. 2,3-dimethylbutane
b. 2,2-dimethylbutane
d. 2-methyl-2-ethylbutane
6. How are 3-methylheptane,3,3-dimethylhexane and 2-ethyl-4-methylpentane related to each other?
a. They are geometric isomers.
c. They are structural isomers.
b. They are homologous.
d. They are optical isomers.
7. Alkenes are hydrocarbons which are represented by the general formula
. Write the molecular formula of
an alkene that has four carbon atoms. Draw all the isomers possible by this formula and write the IUPAC name of
all the isomers.
8. Write the IUPAC name of the following structure:
9. Draw the structure of 3,4,6-triethyl-5-methyloctane.
10. a.
b.
Find the molecular formula of alkenes having five and eight carbon atoms.
Write the condensed structural formulas for these alkenes by putting a double bond between the first and
second carbon atom of the longest carbon atom chain.
11. A hydrocarbon has a formula
. Identify the class of hydrocarbons to which it belongs. Also draw its
condensed structural formula. If it is an alkene or an alkyne, use the double or triple bond at the first carbon of the
longest chain.
12. Draw the structure of the compounds:
a. 3,4-dimethyl-1-cyclobutene
b. 3-ethyl-2,4,6,8-tetramethyl-5-propyl-2,4,6-trinonene
13. Write the IUPAC name of the following compound:
14. Determine whether the given compound is a cis-or trans-isomer.
F
F
A
A
Essay
15. Alkanes are compounds of carbon and hydrogen.
a
Write the molecular formula of an alkane having five carbon atoms.
b
Write the condensed structural formula of an alkane having five carbon atoms.
c
Write all of the structural formulas of branched-chain alkane with the molecular formula from part a.
Organic3
MULTIPLE CHOICE
1. ANS: C
The longest chain has five carbon atoms. The numbering of the chain is done such that all the alkyl groups get the
lowest possible position number. The names selected for the alkyl groups and the parent chain are according to
the IUPAC rules.
STA: 10d
2. ANS: C
The compound is a cyclic hydrocarbon having a five-member carbon ring and a methyl group as a substituent at 1,
2, and 4 positions. The numbering of the cyclic ring is chosen such that the lowest possible numbers are given to
the methyl groups.
STA: 10d
3. ANS: D
The numbering of the carbon ring is chosen such that the lowest position numbers are given to the alkyl groups.
4. ANS: B
The compound is an alkyne because there are two triple bonds between the carbon atoms in the chain. The longest
chain has eight carbon atoms. The ethyl group is attached to carbon atom number 6 and the methyl groups are
attached to carbon atom numbers 6 and 7.
5. ANS: D
The total number of carbon atoms in 2-methyl-2-ethylbutane is seven.
STA: 10d
6. ANS: C
Structural isomers have the same molecular formula, but the atoms are bonded in a different order.
STA: 10d
SHORT ANSWER
7. ANS:
The molecular formula of an alkene that has four carbon atoms is
a.
1-butene
b.
trans-2-butene
.
c.
cis-2-butene
d.
2-methyl-1-propene
PROBLEM
8. ANS:
5-ethyl-3,4,4-trimethyloctane
STA: 10d
9. ANS:
10. ANS:
The general formula for alkenes is
a.
and
b.
and
11. ANS:
Alkyne
12. ANS:
a.
.
b.
13. ANS:
5-ethyl-4-methylnonane
STA: 10d
14. ANS:
Cis isomer
ESSAY
15. ANS:
a.
b.
c.
STA: 10b