Chem 219: Module 2 Exam Questions With 100% Correct
Answers
What are hydrocarbons? - -Molecules composed of only the elements carbon and
hydrogen
What are the two major classes of hydrocarbons? - -Aromatic (benzene) and
aliphatic (alkanes, alkenes, alkynes)
What is the main source of hydrocarbons? - -Fossil fuels like coal, petroleum, and
natural gas obtained by mining and drilling.
What are Alkanes? - -They are saturated hydrocarbons because their skeleton is only
composed of C-C single bonds.
How can alkanes exist? - -They can be linear, branched or exist in ring formations
called cycloalkanes.
Describe a higher/more complex alkane structure: - -They will have more carbons
and/or increased structural diversity.
What is the general formula of Alkanes? - -CnH2n+2
The names of the alkanes reflect? - -The number of carbons present.
How many isomers does each alkane have from 1-10 - -1,1,1,2,3,5,9,18,35,75
Name the first ten prefix of alkanes: - -Methane, ethane, propane, butane, pentane,
hexane, heptane, octane, nonane, decane.
As the molecular weight increases: - -The number of isomers increase.
,Chem 219: Module 2 Exam Questions With 100% Correct
Answers
What does the suffix -ane mean? - -Denotes a saturated hydrocarbon. It is used for
all acyclic saturated alkanes
What is nomenclature? - -The naming of a molecular structure. Historically they were
named after their source, now they are systemic.
Why is nomenclature important? - -Because we cannot remember all the prefixes
since a MF composed of carbons can have several different patterns of connectivity.
What is it meant by the systemic approach? - -There are now methods of naming
molecules so that they all have unique names. You can then determine the structure from
only the name and vice-versa.
IUPAC rules for naming branced alkanes: - -1. Find the parent name by identifying the
longest continuous chain of carbons.
2. Number the parent chain. (begin at the end of the chain nearest to the first branch.)
3. If there are two equally long continuous chains, select the one with most branches.
4. If the first branch point is the same distance, choose the one that gives the lowest
substituents.
5. If the substituents are both equidistant then choose the numbering so the substituent
goes with the higher alphabetic priority.
How are linear alkanes named? - -By combining the prefix indicating the number to
the suffix -ane.
What is a substituent? - -Any group attached to the parent chain.
, Chem 219: Module 2 Exam Questions With 100% Correct
Answers
What are alkyl groups? - -Saturated hydrocarbon substituents. You drop the -yl for -
ane.
A one carbon substituent is a methyl group, four carbon is butyl.
What is a locant? - -A number used to determine the suffix.
Describes the position of substituents.
What happens when two or more of the same type of substituents are present on the
parent chain? Like 3 methyl groups - -Additional prefixes including the number are
added.
How would you describe finding 2,3 dimethylpentane? - -It is a 5 carbon chain, then
it has substituents on numbers 2, 3 and those are methyl groups.
How are IUPAC systematic names put together? - -Locant-(prefix) substituentparent
If two or more different substituents are present on the parent chain then what happens? -
-They are listed alphabetically. Ethyl before methyl
How are halogen atoms as substituents named? - -Change the -ine to -o,
chlorine=chloro, bromine=bromo.
propyl or n-propyl - -CH3CH2CH2
isopropyl - -CH3CHCH3
What does the squiggle bond mean? - -Point of attachment to the parent chain.
Answers
What are hydrocarbons? - -Molecules composed of only the elements carbon and
hydrogen
What are the two major classes of hydrocarbons? - -Aromatic (benzene) and
aliphatic (alkanes, alkenes, alkynes)
What is the main source of hydrocarbons? - -Fossil fuels like coal, petroleum, and
natural gas obtained by mining and drilling.
What are Alkanes? - -They are saturated hydrocarbons because their skeleton is only
composed of C-C single bonds.
How can alkanes exist? - -They can be linear, branched or exist in ring formations
called cycloalkanes.
Describe a higher/more complex alkane structure: - -They will have more carbons
and/or increased structural diversity.
What is the general formula of Alkanes? - -CnH2n+2
The names of the alkanes reflect? - -The number of carbons present.
How many isomers does each alkane have from 1-10 - -1,1,1,2,3,5,9,18,35,75
Name the first ten prefix of alkanes: - -Methane, ethane, propane, butane, pentane,
hexane, heptane, octane, nonane, decane.
As the molecular weight increases: - -The number of isomers increase.
,Chem 219: Module 2 Exam Questions With 100% Correct
Answers
What does the suffix -ane mean? - -Denotes a saturated hydrocarbon. It is used for
all acyclic saturated alkanes
What is nomenclature? - -The naming of a molecular structure. Historically they were
named after their source, now they are systemic.
Why is nomenclature important? - -Because we cannot remember all the prefixes
since a MF composed of carbons can have several different patterns of connectivity.
What is it meant by the systemic approach? - -There are now methods of naming
molecules so that they all have unique names. You can then determine the structure from
only the name and vice-versa.
IUPAC rules for naming branced alkanes: - -1. Find the parent name by identifying the
longest continuous chain of carbons.
2. Number the parent chain. (begin at the end of the chain nearest to the first branch.)
3. If there are two equally long continuous chains, select the one with most branches.
4. If the first branch point is the same distance, choose the one that gives the lowest
substituents.
5. If the substituents are both equidistant then choose the numbering so the substituent
goes with the higher alphabetic priority.
How are linear alkanes named? - -By combining the prefix indicating the number to
the suffix -ane.
What is a substituent? - -Any group attached to the parent chain.
, Chem 219: Module 2 Exam Questions With 100% Correct
Answers
What are alkyl groups? - -Saturated hydrocarbon substituents. You drop the -yl for -
ane.
A one carbon substituent is a methyl group, four carbon is butyl.
What is a locant? - -A number used to determine the suffix.
Describes the position of substituents.
What happens when two or more of the same type of substituents are present on the
parent chain? Like 3 methyl groups - -Additional prefixes including the number are
added.
How would you describe finding 2,3 dimethylpentane? - -It is a 5 carbon chain, then
it has substituents on numbers 2, 3 and those are methyl groups.
How are IUPAC systematic names put together? - -Locant-(prefix) substituentparent
If two or more different substituents are present on the parent chain then what happens? -
-They are listed alphabetically. Ethyl before methyl
How are halogen atoms as substituents named? - -Change the -ine to -o,
chlorine=chloro, bromine=bromo.
propyl or n-propyl - -CH3CH2CH2
isopropyl - -CH3CHCH3
What does the squiggle bond mean? - -Point of attachment to the parent chain.
