Portage Learning CHEM 219 Principles of Organic Chemistry Module 7
Exam
Question 1
Heterocycles (heterocyclic compounds) are _______ organic molecules in which one
________carbon atoms are replaced by heteroatoms - elements other than ________ or
hydrogen. The most common heteroatoms are oxygen, ______and sulfur, but heterocyclics
with other elements are known. MOre than one heteroatoms can be present, and the
heteroatoms can be the same or different
Answer
Cyclic
Or more
carbon
nitrogen
Question 2
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
Heterocyclic compounds by definition do not contain any multiple bonds.
Answer
False
Question 3
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
The main two subclassifications of heterocyclic compounds are aromatic and fused.
Answer
False
Question 4
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
, Heterocyclic compounds are the largest class of organic compounds known.
Answer
True
Question 5
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
Non-aromatic heterocyclic compounds have chemical behavior that is very similar to their
acyclic counterparts.
Answer
True
Question 6
Which is more basic in a heterocyclic compound, a “pyridine-like” nitrogen or a “pyrrole-like”
nitrogen?
Your answer must be at least 2 complete sentences to receive full credit.
Answer
In general, when the nitrogen atom of an aromatic heterocycle is a participating in a p bond,
then the lone pair occupies an sp2 orbital in the same plane as the ring and is available to react
as a weak base. These nitrogen atoms can be viewed as being “pyridine-like”. When the
nitrogen atom of an aromatic heterocycle has single bonds only, then the lone pair participates
in the conjugated pi system to create aromaticity and is not available to react as a weak base.
These nitrogen atoms are referred to as “pyrrole-like”
Question 7
Identify each of the following five-membered aromatic heterocyclic compounds.
Exam
Question 1
Heterocycles (heterocyclic compounds) are _______ organic molecules in which one
________carbon atoms are replaced by heteroatoms - elements other than ________ or
hydrogen. The most common heteroatoms are oxygen, ______and sulfur, but heterocyclics
with other elements are known. MOre than one heteroatoms can be present, and the
heteroatoms can be the same or different
Answer
Cyclic
Or more
carbon
nitrogen
Question 2
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
Heterocyclic compounds by definition do not contain any multiple bonds.
Answer
False
Question 3
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
The main two subclassifications of heterocyclic compounds are aromatic and fused.
Answer
False
Question 4
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
, Heterocyclic compounds are the largest class of organic compounds known.
Answer
True
Question 5
Determine if the following statement regarding the structure of heterocyclic molecules is true or
false:
Non-aromatic heterocyclic compounds have chemical behavior that is very similar to their
acyclic counterparts.
Answer
True
Question 6
Which is more basic in a heterocyclic compound, a “pyridine-like” nitrogen or a “pyrrole-like”
nitrogen?
Your answer must be at least 2 complete sentences to receive full credit.
Answer
In general, when the nitrogen atom of an aromatic heterocycle is a participating in a p bond,
then the lone pair occupies an sp2 orbital in the same plane as the ring and is available to react
as a weak base. These nitrogen atoms can be viewed as being “pyridine-like”. When the
nitrogen atom of an aromatic heterocycle has single bonds only, then the lone pair participates
in the conjugated pi system to create aromaticity and is not available to react as a weak base.
These nitrogen atoms are referred to as “pyrrole-like”
Question 7
Identify each of the following five-membered aromatic heterocyclic compounds.
