Download Chapter one: Unsaturated Hydrocarbons

Chapter one: Unsaturated Hydrocarbons
Questions and Answers
1. . The first and simplest alkane is
a) Ethane
b) Propane
c) Butane
d) Methane
2. Which of the following classes of organic compounds is NOT a hydrocarbon
a. Cycloalkanes b) alkenes c) alcohols d) alkanes
3. What organic compound is characterized by the presence of a single bond?
a) Alkanes
b) alkynes
c) alkenes
4. When one hydrogen atom of alkane is removed then it is called?
a) Alkane b) alkyl
c) alkynes d) saturated hydrocarbons
5. Hydrocarbons combust in abundant oxygen to form:
a. Carbon dioxide and carbon monoxide
b. Smaller hydrocarbons such as methane
c. Carbon dioxide and water
d. Carbon and water
6. What is the difference between
a. Cyclic an acyclic hydrocarbon?
Cyclic: it has rings of carbon atoms or it contains closed chain
Acyclic: it has no rings of carbon atoms. Or it contains open chain
b. continuous- chain alkane and branched-chain alkane
Acyclic alkanes are subdivided as continuous- chain and branched alkanes
Continuous- chain alkane: is an alkane in which all carbon atoms are connected in
a continuous non-branching chain.
Branched-chain alkane: is an alkane in which one or more branches (of carbon
atoms) are attached to a continuous chain of carbon atoms
7. What is an alkyl group? Name and draw the structure derived from ethane , propane , and
butane
An alkyl group is the group of atoms that would be obtained by removing a hydrogen
atom from an alkane
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8. Name each the following compounds using the systematic name (IUPAC)
CH3
CH3
|
a. CH3CHCH2CH3
|
b. CH3CH2CCH2CH3
|
C
H
3
c.
CH3 CH3
CH3
|
|
|
CH3CHCHCH2CHCH3
CH3 CH2CH3 CH3
|
|
|
d. CH3CHCHCH2CHCH2CH2CH3
CH2CH2CH3
|
e. CH3CH2CH2CHCH2CH2CH2CH2CH3
f.
g.
2
a.
b.
c.
d.
e.
f.
g.
2-methylbutane
3,3-dimethylpentane
2,3,5-trimethylhexane
3-ethyl-2,5-dimethyloctane
4-propylnonane
3,3,6-trimethylnonane
3,3,5-trimethylheptane
9. Complete and balance each of the following combustion reaction of alkanes?
A. C5H12 (g) + 8O2 (g) ——> 5 CO2 + 6 H2O
B. 2C2H6 (g) +
7O2 (g)
——> 4 CO2 + 6 H2O
10. Pentane has three isomers with the same molecular formula C5H12
A) What is an isomer? Isomers are compounds that have the same molecular
formula but that differ in the way the atoms are arranged
B) Draw the structural formula of three isomers of pentane
11. Explain the difference between
A combustion reaction and halogenation reaction
A combustion reaction is a chemical reaction between a substance and oxygen
A halogenation reaction is a chemical reaction between a substance and a halogen
12. Draw the structure corresponding to each IUPAC name
A) 2, 3-dichlorohexane
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B) 1 3-dimethylcyclopentane
C) Ethylcyclpentane
3-chloro-5-methylhexane
13. Look at the reaction represented by the equation below, classify each reaction as
a) Substitution
b) Addition
c) combustion
i.
CH2=CH2+H2 ——>CH3CH3 Addition
ii.
CH3-CH2-CH3 + 5 O2 ——> 3 CO2 + 4 H2O + heat (combustion)
iii. CH4 + Cl2
——> CH3Cl + HCl Substitution
14. What is the general formula of
a. Cycloalkane: CnH2n
b. Alkanes: CnH2n+2
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15. Name the following compounds
a)
b)
c)
d)
Methylcyclopentane
Isopropylcyclohexane
1,4-dimethylcyclobutane
1-bromo-2,3-dimethylpentane
16. Define the following terms, give an example
a. Organic chemistry: the study of hydrocarbons and their derivatives.
b. Hydrocarbon: is a compound that contains only carbon and hydrogen atoms
c. Hydrocarbon derivative is a compound that contains carbon and hydrogen and one
or more additional elements.
d. unsaturated hydrocarbon is a hydrocarbon in which one or more carbon–carbon
multiple bonds (double bonds, triple bonds, or both) are present
e. Saturated hydrocarbon is a hydrocarbon in which all carbon–carbon bonds are
single bonds.
f. an alkane : a saturated hydrocarbon in which the carbon atom arrangement is
acyclic
g. Constitutional isomers are isomers that differ in the connectivity of atoms
h. Cycloalkane is a saturated hydrocarbon in which carbon atoms connected to one
another in a cyclic (ring) arrangement are present.
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i. Stereoisomers are isomers that have the same molecular and structural formulas
but different orientations of atoms in space
j. Cis– trans isomers are isomers that have the same molecular and structural
formulas but different orientations of atoms in space because of restricted rotation
about bonds.
k. Halogenoalkanes is an alkane derivative in which one or more halogen atoms are
present
l. A substitution reaction is a chemical reaction in which part of a small reacting
molecule replaces an atom or a group of atoms on a hydrocarbon or hydrocarbon
derivative
17. State physical and chemical properties of alkanes and cycloalkanes
18. Explain why carbon is able to form so many more compounds than most other elements.
Carbon atoms have the unique ability to bond to each other in a wide variety of ways
that involve long chains of carbon atoms or cyclic arrangements (rings) of carbon
atoms.
19. Why it is that alkanes, unlike alkenes, have no geometric isomers?
There is free rotation about all carbon–carbon bonds
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