Chemistry 123
Worksheet 10 Notes
1.
Spring 2004
May 26, 2004
Oregon State University
Dr. Richard Nafshun
Draw the line structure of an alkane that contains ten carbon atoms. What is the
chemical formula of this compound? What is the condensed structural formula of
this compound? Draw the line structures of two isomers of this compound. What
are their chemical formulae (explain)? What are their condensed structural
formulae? What are the names of these three structures?
C10H22 (CnH2n+2)
CH3(CH2)8CH3
C10H22 (CnH2n+2)
CH3CH(CH3)(CH2)6CH3
C10H22 (CnH2n+2)
CH3CH2CH(CH3)(CH2)5CH3
decane
2-methyl nonane
3-methyl nonane
These are three isomers of C10H22 (there are many more).
2.
Sketch an alkene that contains three carbon atoms. Name it. Write a reaction for
your alkene and Br2 in UV.
Br
+
Br2
(in UV) →
propene
Br
1,2-dibromopropane
This reaction is an example of the addition to an alkene. The pi-bond is broken.
3.
Sketch an alkyne that contains three carbon atoms. Name it. Write a reaction for
your alkyne and two moles of Cl2 in UV.
Cl
Cl
+
propyne
2 Cl2 (in UV) →
Cl
Cl
1,1,2,2-tetrachloropropane
4.
Sketch an alcohol that contains six carbon atoms.
OH
2-hexanol
Sketch a carboxylic acid that contains five carbon atoms.
O
OH
(Name happens to be pentanoic acid)
Sketch an aldehyde that contains six carbon atoms.
O
H
(Name happens to be hexanal)
Sketch a ketone that contains five carbon atoms.
O
(Name happens to be 2-pentanone)
Sketch an ether that contains three carbon atoms.
O
(Name happens to be ethyl methyl ether)
5.
Sketch an ester that contains six carbon atoms. Identify the alcohol and carboxylic
acid that form this ester with the loss of water.
O
O
One of the six-carbon esters...
O
OH
and the alcohol...
HO
and the carboxylic acid that
can produce it.
6.
Sketch a carboxylic acid that is a benzene derivative. Sketch the ester that is formed
when your carboxylic acid reacts with ethanol.
O
O
OH
O
OH
Benzoic acid
(the carboxylic acid)
7.
ethanol
the ester formed from benzoic acid
and ethanol
Sketch an amine that contains six atoms. Sketch the amide that is formed when
your amine reacts with ethanol acetic acid (note this change).
N
O
N
A six-carbon amine
8.
O
OH
acetic acid
the amide formed
What is meant by a condensation reaction? Give an example.
Water is lost during a condensation reaction. Examples include: the formation of an ester
from an alcohol and a carboxylic acid, the formation of an amide from an amine and a
carboxylic acid.
9.
What is meant by an addition reaction? Give an example.
Addition is to make an addition to a molecule. An example is the addition of a small
molecule (such as Br2) to an alkene.
Br
+
Br2
propene
10.
(in UV) →
Br
1,2-dibromopropane
What is meant by a substitution reaction? Give an example of one.
Substitution is to substitute an atom on a molecule. An example is electrophilic aromatic
substitution.
Cl
+
in the presence of AlCl3
→
+ HCl
11.
The reaction of hydrochloric acid and ethene produces:
HCl
Cl
→
+
12.
C6H12O6 (aq)  2 CH3CH2OH (aq) + 2 CO2 (g) occurs in the absence of air and in
the presence of yeast. This is fermentation.
13.
The building blocks of proteins are amino acids.
14.
What is chiral? Sketch a molecule that contains three chiral carbons.
A molecule is chiral if it cannot be superimposed on its mirror image. A carbon in a
molecule is chiral if it has four different groups attached to it. CH2BrF is not chiral.
CHBrClF is.
15.
What are the products of benzene and chloroethane in the presence of AlCl3?
Cl
in the presence of AlCl3 →
+
16.
Sketch Ala-Ala-Gly-Cys-Tyr.
H R1 O
H R2 O
H R3 O
H R4 O
H R5 O
H N C C
N C C
N C C
N C C
N C C OH
H
H
H
H
Where:
R1 is CH3
R2 is CH3
R3 is H
R4 is CH2SH
R5 is
CH2
OH
H
+ HCl
17.
Write the mechanism for the electrophilic aromatic substitution of benzene with 3chloropentane in the presence of AlCl3.
H
H
H
H
H
H
Cl
+
in the presence of AlCl3 →
Step1: The catalyst strips Cl- from 3-chloropentane:
Cl
+
AlCl3 →
+
AlCl4-
Step 2: The electrophile attacks the benzene ring. The new bond is formed using a pair
of pi-electrons from benzene:
H
H
H
H
H
H
Step 3: The leaving group H+ leaves. The pi-electrons are returned:
+
H
H
H
H
H
H
Step 4: The catalyst is regenerated:
AlCl4- +
H+
→
AlCl3
+
HCl
Net Reaction:
H
H
H
H
H
H
Cl
+
in the presence of AlCl3
→
H
H
H
H
H
18.
+
HCl
What polymer is formed by the reaction of HOCH2OH and
HOOCCH2CH2CH2CH2COOH?
This is a condensation polymerization. Water is lost between the alcohol and carboxylic
acid:
O
O
O
O
||
||
||
||
HOCH2OH + HOCCH2CH2CH2CH2COH → HOCH2OCCH2CH2CH2CH2COH
water will leave
The carboxylic acid group on the right is still in tact and will react with an alcohol group
from another HOCH2OH molecule. The alcohol group on the left is still in tact and will
react with a carboxylic acid group from another HOOCCH2CH2CH2CH2COOH
molecule.
The polymer may be represented as:
O
O
||
||
-[-CH2OCCH2CH2CH2CH2CO-]nWhere n is a large number representing a large number of these repeat units make up the
polymer.
19.
Define: trans-, unsaturated, saturated, and omega-3 fats. What is meant by
partially hydrogenated vegetable oil?
trans- fats
have the trans- conformation about a double bond.
unsaturated fats
have double bonds (they are not saturated with hydrogens).
saturated fats
have no double bonds (any double bonds have been saturated with
hydrogen).
omega-3 fats
have a double bond located at the third carbon from the end of the
chain. The term omega-3 is used because omega indicates the first
carbon at the end of the chain and the 3 indicates the third carbon
atom in.
partially hydrogenated vegetable oil
some, but not all, of the double bonds
present in the carbon chains have been hydrogenated (had
hydrogen added across the pi-bond).
20.
What polymer is formed by the reaction of a radical initiator and CF(C6H5)CF2?
-[-CF(C6H5)CF2-]nThe radical initiator breaks the pi-bond in the monomer causing it to become a larger
radical and attacking another monomer unit.
F
F
C
F
R C
C
F
F
+
monomer
F
C
R•
initiator
→
new, larger, radical
(The dot inside the right carbon is to
represent the radical electron)
(This new radical will attack a
monomer unit and this process will
continue...)
21.
What polymer is formed by the reaction of HOOCH2CH2CH2COOH and
HNCH2CH2CH2CH2NH?
This is a condensation polymerization. Water is lost between the amine and carboxylic
acid:
H
H
O
O
|
|
||
||
HNCH2CH2CH2CH2NH + HOCCH2CH2COH →
water will leave
H
H O
O
|
| ||
||
HNCH2CH2CH2CH2NCCH2CH2COH
new amide
The carboxylic acid group on the right is still in tact and will react with an amine group
from another HNCH2CH2CH2CH2NH molecule. The amine group on the left is still in
tact and will react with a carboxylic acid group from another HOOCCH2CH2COOH
molecule.
What two dipeptides can be formed from Tyr and Gly?
H R1 O
H N C C
H R2 O
N C C OH
H
H
Tyr-Gly has the above structure where R1 is:
CH2
OH
and R2 is:H.
Gly-Tyr has the above structure where R2 is:
CH2
OH
and R1 is:H.
Are Tyr-Gly and Gly-Tyr different molecules? Yes.
Identify a tripeptide that can be formed from Glu, Asn, and Val.
H R1 O
H N C C
H R2 O H R3 O
N C C N C C OH
H
H
H
Glu-Asn-Val has the above structure where:
R1 is CH2CH2COOH
and
R2 is CH2CONH2
and
R3 is CH(CH3)2.
How many tripeptides can be made from a single Glu, a single Asn, and a single Val?
(The answer is in my name at the top of the first page :-)
22. Below are the structure of Talose and Gulose:
HO
HO
HO
H
CHO
H
H
H
OH
CH 2OH
H
H
HO
H
CHO
OH
OH
H
OH
CH 2OH
How many chiral centers are there in each sugar? Label them. Assign D or L to each sugar and
explain how you arrived at that conclusion.
There are 4 Chiral centers in each sugar (all the carbons between the aldehyde and alcohol part at
the bottom). The very bottom carbon is not chiral since it has 2 Hydrogens on it. Both
sugars are D sugars since the very bottom chiral carbon has the OH on the right side.