CHEM 219 Module 2 Exam
Questions with Elaborate Answers
(Latest Edition)
1. Substituent - ANSWER an atom or group of atoms that can take the place of
a hydrogen atom on a parent hydrocarbon molecule
2. Alkyl groups - ANSWER groups of atoms that are formed when one
hydrogen atom is removed from an alkane molecule
3. What are hydrocarbons? - ANSWER Molecules composed of only the
elements carbon and hydrogen
4. What are the two major classes of hydrocarbons? - ANSWER Aromatic
(benzene) and aliphatic (alkanes, alkenes, alkynes)
5. What is the main source of hydrocarbons? - ANSWER Fossil fuels like
coal, petroleum, and natural gas obtained by mining and drilling.
6. What are Alkanes? - ANSWER They are saturated hydrocarbons because
their skeleton is only composed of C-C single bonds.
7. How can alkanes exist? - ANSWER They can be linear, branched or exist in
ring formations called cycloalkanes.
,8. What happens when two or more of the same type of substituents are present
on the parent chain? Like 3 methyl groups - ANSWER Additional prefixes
including the number are added.
9. How would you describe finding 2,3 dimethylpentane? - ANSWER It is a 5
carbon chain, then it has substituents on numbers 2, 3 and those are methyl
groups.
10.How are IUPAC systematic names put together? - ANSWER Locant-
(prefix) substituentparent
11.If two or more different substituents are present on the parent chain then
what happens? - ANSWER They are listed alphabetically. Ethyl before
methyl
12.How are halogen atoms as substituents named? - ANSWER Change the -ine
to -o, chlorine=chloro, bromine=bromo.
13.propyl or n-propyl - ANSWER CH3CH2CH2
14.isopropyl - ANSWER CH3CHCH3
15.What does the squiggle bond mean? - ANSWER Point of attachment to the
parent chain.
16.Butyl or n-butyl - ANSWER -CH2CH2CH2CH3
17.sec-butyl - ANSWER CH3CHCH2CH3
, 18.Isobutyl would be alphabetized as? While sec-butyl would be alphabetized
as? - ANSWER I, B
19.What does R represent? - ANSWER It is a generic/wildcard notation in
organic structure.
Any alkyl group.
This is known as R-group notation.
20.Why is R chosen? - ANSWER It is not on the chart anywhere.
21.What is the important thing to know about the physical properties of alkanes.
- ANSWER They will show similar trends in terms of their physical
properties.
22.What does the physical properties of a molecule refer to? - ANSWER
Characteristics like melting point, boiling point, density, solubility.
23.How do you compare the boiling point of alkanes? - ANSWER The longer
the length of carbon, the higher the Boiling point. When it is branched, it can
have a higher boiling point, as long as it isn't the parent chain that is
branched.
24.Are alkanes soluble in water? - ANSWER They are water-insoluble.
25.Are alkanes polar or non-polar? - ANSWER Almost non-polar
Questions with Elaborate Answers
(Latest Edition)
1. Substituent - ANSWER an atom or group of atoms that can take the place of
a hydrogen atom on a parent hydrocarbon molecule
2. Alkyl groups - ANSWER groups of atoms that are formed when one
hydrogen atom is removed from an alkane molecule
3. What are hydrocarbons? - ANSWER Molecules composed of only the
elements carbon and hydrogen
4. What are the two major classes of hydrocarbons? - ANSWER Aromatic
(benzene) and aliphatic (alkanes, alkenes, alkynes)
5. What is the main source of hydrocarbons? - ANSWER Fossil fuels like
coal, petroleum, and natural gas obtained by mining and drilling.
6. What are Alkanes? - ANSWER They are saturated hydrocarbons because
their skeleton is only composed of C-C single bonds.
7. How can alkanes exist? - ANSWER They can be linear, branched or exist in
ring formations called cycloalkanes.
,8. What happens when two or more of the same type of substituents are present
on the parent chain? Like 3 methyl groups - ANSWER Additional prefixes
including the number are added.
9. How would you describe finding 2,3 dimethylpentane? - ANSWER It is a 5
carbon chain, then it has substituents on numbers 2, 3 and those are methyl
groups.
10.How are IUPAC systematic names put together? - ANSWER Locant-
(prefix) substituentparent
11.If two or more different substituents are present on the parent chain then
what happens? - ANSWER They are listed alphabetically. Ethyl before
methyl
12.How are halogen atoms as substituents named? - ANSWER Change the -ine
to -o, chlorine=chloro, bromine=bromo.
13.propyl or n-propyl - ANSWER CH3CH2CH2
14.isopropyl - ANSWER CH3CHCH3
15.What does the squiggle bond mean? - ANSWER Point of attachment to the
parent chain.
16.Butyl or n-butyl - ANSWER -CH2CH2CH2CH3
17.sec-butyl - ANSWER CH3CHCH2CH3
, 18.Isobutyl would be alphabetized as? While sec-butyl would be alphabetized
as? - ANSWER I, B
19.What does R represent? - ANSWER It is a generic/wildcard notation in
organic structure.
Any alkyl group.
This is known as R-group notation.
20.Why is R chosen? - ANSWER It is not on the chart anywhere.
21.What is the important thing to know about the physical properties of alkanes.
- ANSWER They will show similar trends in terms of their physical
properties.
22.What does the physical properties of a molecule refer to? - ANSWER
Characteristics like melting point, boiling point, density, solubility.
23.How do you compare the boiling point of alkanes? - ANSWER The longer
the length of carbon, the higher the Boiling point. When it is branched, it can
have a higher boiling point, as long as it isn't the parent chain that is
branched.
24.Are alkanes soluble in water? - ANSWER They are water-insoluble.
25.Are alkanes polar or non-polar? - ANSWER Almost non-polar
