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WorksheetsMIDTERM EXAM
Total questions: 60
Worksheet time: 2hrs 0mins
What is the name of the compound with the structural formula, CH3CH(CH3)CH(CH3)CH2CH3?
heptane
2,3-Dimethylpentane
2,3-Methylpentane
3,4-Dimethylpentane
The number of structural isomers with the molecular formula C5H12 is...
2
3
4
5
Which of the following could not be the molecular formula for an alkane
molecule?
C3H8
C4H12
CH4
C20H42
The representation CH3–CH3 for the alkane ethane is an example of
a molecular formula.
a condensed structural formula.
an expanded structural formula.
a skeletal structural formula.
Which of the following is a correct alkane structural formula?
CH3–CH2–CH3
CH3–CH3–CH2
CH2–CH2–CH2
CH2–CH3–CH2
Constitutional isomerism is possible in alkanes only if the number of carbon atoms present is
4 or more.
5 or more.
an even number.
an odd number.
Which of the following alkanes has the IUPAC name 2-methylbutane?
How many carbon atoms are present in the alkane whose IUPAC name is 2,2,4-trimethylpentane?
five
seven
eight
nine
How many hydrogen atoms are present in the molecule 3,5-dimethyloctane?
eighteen
twenty
twenty-two
twenty-four
In which of the following pairs of alkanes are the two members of the pair constitutional isomers?
Hexane and 2-Methylhexane
2,3-Dimethylhexane and 2,3-Dimethylheptane
Butane and Pentane
2-Methylpentane and 2,3-Dimethylbutane
In which of the following alkanes are two secondary carbon atoms present?
The minimum number of carbon atoms required to form a branched-chain alkane and a branched-chain alkyl group are, respectively,
three and two.
four and five.
three and four.
one and three.
Which of the following statements concerning saturated hydrocarbons is incorrect?
Every carbon atom present has four bonds.
All bonds present are single bonds.
Every carbon atom present must be bonded to at least two hydrogen atoms.
more than one correct response
Which of the following compounds is a constitutional isomer of
CH3–CH2–CH2–CH2–CH3?
2-Methylpentane
2-Methylbutane
2,2-Dimethylbutane
more than one correct response
Which of the following alkane structures contain both secondary and tertiary carbon atoms?
more than one correct response
Select the incorrect statement regarding alkanes.
It is otherwise known as Paraffin
It is an acyclic saturated hydrocarbon
In alkanes, C-C bonds are single
Alkanes have the general formula CnH2n
An alkane with 6 carbon atoms will have how many hydrogen atoms?
11
12
13
14
Identify the correct alkane name for the molecular formula C30H62.
Propdecane
Eicosane
Triacontane
Dodecane
The substituent in the chain is named by replacing the “ane” in the alkanes by _________.
ene
ic
one
yl
Conformations are different arrangements of atoms that can be converted into one another by rotation about ___________.
Covalent bond
Double bond
Single bond
Triple bond
The energy present in the eclipsed conformation of ethane is called ___________.
Rotational energy
Torsional energy
Enantiomeric energy
Potential energy
The conformations in which the two methyl groups are as far apart as possible at 180o angle is called ___________.
anti conformations
Staggered conformations
Eclipsed conformations
Gauche
The more stable conformation where in all six C-H bonds are far as possible when viewed in a Newman projection.
anti conformations
Staggered conformations
Eclipsed conformations
Gauche
The H-H interaction in a alkane conformation is caused by ___________.
Lateral strain
Shear strain
Steric strain
Torsional strain
Which of the following is least stable?
Anti conformation
Gauche conformation
Staggered conformation
Eclipsed conformation
The best classification for the following compound is: _____ .
aldehyde
ester
ketone
carboxylic acid
The functional group given below is characteristic of organic _____ .
ketones
acids
aldehydes
esters
What is the IUPAC name for the following compound?
1,3-Pentamethylpropane
1,1,3,3-Tetramethylbutane
2,4,4-Trimethylpentane
2,2,4-Trimethylpentane
Which Newman projection shows the most stable conformation of the following compound?
A
B
C
D
Give the IUPAC name of this structure
3-Methylheptane
3-Ethylhexane
2,3-Diethylbutane
3-Ethylbutane
Give the IUPAC name of this structure.
3-Ethyl-2,3-dimethylpentane
2-Methyl-3,3-methylethylpentane
2,3-Methyl-3-ethylpentane
3-Methyl-2,3-dilethylpentane
Give the IUPAC name of this structure.
2,3-Dimethylhexane
3,4-Ethylmethylhexane
3-Ethyl-4-methylhexane
3-Ethyl-4-ethylhexane
Give the IUPAC name of this compound.
Hexane
3,3-Dimethylpentane
2,2-Dimethylhexane
2-Methylpentane
Ethers are formed by attachment of
two alkyl groups to same oxygen atom
two alkyl group to different oxygen atoms
three alkyl groups to one oxygen atom
four alkyl groups to one oxygen atom
What is the IUPAC name of the following compound?
1-Isopropyl-2,5-dimethylcyclohexane
1,4-Dimethyl-2-isopropylcyclohexane
2-Isopropyl-1,4-dimethylcyclohexane
1,4-Dimethyl-3-isopropylcyclohexane
What is the IUPAC name of the following compound?
cis-1-Isopropyl-2-methylcyclopentane
cis-1-Tert-butyl-2-methylcyclopentane
trans-1-Isopropyl-4-methylcyclopentane
trans-1-Tert-butyl-2-methylcyclopentane
Which of the following is an acceptable IUPAC name?
1-Methyl-2-ethylcyclopentane
1-Ethyl-2-methylcyclopentane
2-Methyl-1-ethylcyclopentane
2-Ethyl-1-methylcyclopentane
Which of the following pairs of structures are constitutional isomers of one another?
1
2
3
4
The molecular formula for cycloalkanes would be identified as which of the following?
CH
CHn
CnH2n
CnH
The compound cyclobutane contains how many C-H atoms?
Five
Seven
Three
Four
What is the molecular formula for cyclopropane?
C4H6
C4H8
C3H8
C3H6
Name this molecule
nonane
decane
cycloheptane
cyclononane
Name this molecule
Cyclohexane
1,2-Dimethylcyclohexane
1,2-Methylcyclohexane
1,6-Dimethylcyclohexane
The relationship of the following two structures is
structural isomers
conformational isomers
the same
stereoisomers
Which drawing represents the most stable conformation of cis-1-Tert-butyl-4-methylcyclohexane.
A
B
C
D
Which of the following molecules is the least stable ?
A
B
C
D
Which of the following represents the most stable conformation of cis-1- isopropyl-4-methylcyclohexane?
A
B
C
D
The relationship of the following two molecules is best described by
structural isomers
geometric isomers
homologous
conformational isomers
Which structure is different from the following?
Which conformation is most unstable?
Which of the following statements regarding cycloalkanes is wrong?
Any disubstituted cycloalkane can have cis-trans isomers.
The planar form of any cycloalkane with a ring larger than cyclopropane will not be the most stable conformation.
Cyclopentane is nonplanar to avoid the torsional strain between adjacent C-H bonds.
The least strained form of any unsubstituted cycloalkane is the chair conformation of cyclohexane.
Which of the following statements regarding chair cyclohexane is wrong?
The dihedral angle of the two axial bonds on adjacent carbons is 180°.
The dihedral angle of the two equatorial bonds on adjacent carbons is 60°.
The dihedral angle between the axial bond and the equatorial bond on adjacent carbons is 120°.
The axial hydrogen atoms on C1, C3, and C5 form an equilateral triangle (as do C1, C3, and C5 themselves and the equatorial hydrogens on them).
Label the pair of compounds below as:
conformational isomers
stereoisomers
constitutional isomers
identical
Label the pair of compounds below as:
conformational isomers
stereoisomers
constitutional isomers
identical
Label the pair of compounds below as:
conformational isomers
stereoisomers
constitutional isomers
identical
Label the pair of compounds below as:
conformational isomers
stereoisomers
constitutional isomers
identical
Which of the labeled bonds in the structure are equatorial bonds?
a
b
c
d
e
Which of the labeled bonds are trans to bond b?
a
b
c
d
e
What is the IUPAC name of the following compound?
trans-1-Isopropyl-4-methylcyclohexane
cis-1-Isopropyl-4-methylcyclohexane
cis-2-Isopropyl-5-methylcyclohexane
cis-1-Tert-butyl-4-methylcyclohexane
The general formula for alkanes is...
CnH2n-2
CnH2n
CnH2n+2
CnH3n
