CHM 201 C - Examination 1 - FORM 0 - 29 September 2004
Each of the following 30 questions is worth 3 1/3 points for a
total of 100 points.
01. Organic compounds are currently defined as compounds that:
a) are hydrocarbons
b) are necessary to life
c) contain carbon
d) are not manufactured by human beings
e) come from living or once-living substances
02. In its 3-dimensional shape, methane most closely resembles a:
a) 3-sided tent b) flat square
c) tall, cylindrical stack of pennies
d) cubical shipping box e) sphere
03. Isomers are different compounds that:
a) share the same molecular formula
b) are composed of the same elements
c) have the same molecular structure
d) share the same molecular configuration
e) have the same melting point, boiling point, and other physical
characteristics
04. Neopentane is an isomer of:
a) 2,2-dimethylpropane b) 2-methylbutane c) 2,2-dimethylbutane
d) 2-methylpentane e) isobutane
Use the following in answering questions 05 and 06
H. C6H16 I. C12H26 J. C8H16 K. C10H18 L. C15H26
05. Represents an alkane: a) L b) H c) I d) K e) J
06. Represents an alkene: a) H b) I c) J d) K e) L
07. A molecule that contains more 2o hydrogens than 1o hydrogens
is: a) butane b) hexane c) 1,3,5-trimethylcyclohexane
d) 2-methylhexane e) methylcyclobutane
08. The combination of a sec-butyl group and an isobutyl group
produces:
a) 2,4-dimethylhexane
b) 2,5-dimethylhexane
c) 2,4-dimethylpentane
d) 3,4-dimethylhexane
e) 2,5-dimethylheptane
09. An acceptable name for the Newman projection
is: a) gauche-butane b) noneclipsed-butane c) trans-butane
d) contra-butane e) anti-butane
10. The Newman projection
represents an eclipsed conformation of:
a) 2,3-dimethylbutane b) isopentane c) 2,2,3-trimethylbutane
d) 2,2-dimethylbutane e) neopentane
11. The IUPAC name of
CH3-CH-CH3
|
CH3-CH-CH2-CH2-CH2-CH-CH3
|
CH2-CH3
is:
a) 3-methyl-7-isopropyloctane
b) 3-ethyl-2,7- dimethylnonane
c) 2-ethyl-6-isopropyloctane
d) 2-ethyl-7-methyloctane
e) 2,3,7-trimethylnonane
12. CH2=CH-CH2-Br is commonly known as:
a) allyl bromide
b) vinylmethylene bromide
c) isoprenyl bromide
d) vinyl bromide
e) methylene bromide
13. The total number of isomeric hydrocarbons of molecular
formula C4H8, including all configurational isomers, and both
cyclic and acyclic (noncyclic) hydrocarbons, is:
a) 5 b) 2 c) 6 d) 3 e) 4
14. A conformation exhibiting CH3/CH3 eclipsing cannot form in:
a) butane b) isopentane c) 3-methylhexane
d) 2,3-dimethylbutane e) isobutane
Use the following Newman projections for Questions #15 and #16
15. The Newman projection that represents the most stable (lowest
energy) dimethylcyclohexane is: a) Q b) S c) U d) T e) R
16. trans-1,3-Dimethylcyclohexane is represented by:
a) only Q and S
b) only Q, R, S, and T
c) (none of the Newman projections represent trans-1,3-
dimethylcyclohexane)
d) only R and T
e) only U
17. Bridgehead hydrogens occur in:
a) cis-1,3-dimethylcyclohexane
b) trans-1,2-dimethylcyclopropane
c) vinyl bromide
d) cis-3-hexene
e) trans-decalin
18. Given the following values for bond dissociation energies
Bond D (kJ/mol)
Br-Br 193
CH3-Br 293
CH3-NH2 335
H-Br 366
H-H 436
CH3-H 438
NH2-H 449
the absolute numerical value (ignoring the algebraic sign) of H
for the reaction
CH3-Br + NH3 ---> CH3-NH2 + HBr
is: a) 308 b) 41 c) 1343 d) 194 e) 621
19. The amount of heat absorbed or released in a reaction (per
mole of the participating chemicals) is most closely related to:
a) the change in entropy that occurs as the reaction progresses
b) the rate of the reaction
c) the change in Gibbs free energy produced by the reaction
d) the net change in the number of molecules that occurs during
the reaction
e) the difference in bond strengths between reactants and
products
20. The bond dissociation energy of H2 is 436 kJ/mol. This means
that:
a) according to the equation E=mc2, the total energy content of
all the matter in H2 is 436 kJ/mol
b) the formation of the covalent bond of H-H releases 436 kJ/mol
c) 436 kJ/mol must be added to independent H atoms to create
an H2 molecule
d) molecular H2 releases 436 kJ/mol when it dissociates into two,
infinitely separated hydrogen atoms
e) molecular H2 releases 436 kJ/mol when it combines with
oxygen to form H2O
21. The difference between the Gibbs free energy of the products
of a reaction and the Gibbs free energy of its reactants is:
a) TS b) S c) H-TS d) G-TH e) H
22. Of the following, the true statement is:
a) Weak covalent bonds release energy to their surroundings when
they form, but strong covalent bonds absorb energy from
their surroundings when they form.
b) Weak covalent bonds absorb energy from their surroundings when
they form but strong covalent bonds release energy to their
surroundings when they form.
c) Both weak and strong covalent bonds absorb energy from their
surroundings when they break.
d) Weak covalent bonds release energy to their surroundings when
they break, but strong covalent bonds absorb energy from
their surroundings when they break.
e) Both weak covalent bonds and strong covalent bonds release
energy to their surroundings when they break.
23. The index of hydrogen deficiency of
1-methyl-1,4-cyclohexadiene is: a) 4 b) 3 c) 2 d) 5 e) 1
24. Of the following compounds,
F CH3 I Cl CH3 H F CH2-OH
\ / \ / \ / \ /
C=C C=C C=C C=C
/ \ / \ / \ / \
Br H CH3 CH2-CH3 I CH2-CH3 Br CH3
the total number of E isomers represented is:
a) 4 b) 1 c) 3 d) 2 e) 0
25. Of the following, the one that cannot exist as geometric
(configurational)isomers is:
a) 1,2-dibromoethene
b) 1,4-dichlorocyclohexane
c) 1,1-dimethylcyclohexane
d) 1,3-dibromocyclobutane
e) 2-pentene
26. Of the following, the one that cannot exist as
conformational isomers is:
a) butane
b) 2-pentene
c) 2,3-dimethylbutane
d) propene
e) ethene
27. Of the following, the one that releases the greatest amount
of heat (in kJ/mol) during catalytic hydrogenation is:
a) CH3
\
C=CH2
/
CH3
b) CH2=CH2
c) CH2
/ \
CH2 CH
| º
CH2 CH
\ /
CH2
d) CH3 CH3
\ /
C=C
/ \
H H
e) CH3 H
\ /
C=C
/ \
H CH3
28. The rate-determining step in the addition of HX to an alkene
is:
a) addition of X to the carbocation
b) loss of a proton from the carbocation
c) rearrangement of the product to form the Markovnikov isomer.
d) carbocation formation
e) ionization of HX
29. The order of thermodynamic stability of alkyl carbocations
is:
a) GREATEST 1o>2o>3o>methyl LEAST
b) GREATEST 2o>3o>methyl>1o LEAST
c) GREATEST methyl>1o>2o>3o LEAST
d) GREATEST 3o>2o>1o>methyl LEAST
e) GREATEST 1o>methyl>3o>2o LEAST
30. The incorrect IUPAC name among the following is:
a) 4-methylcyclobutene
b) 5-bromo-2-chloro-2-hexene
c) 3-ethyl-3-hexene
d) 3,4-dimethylcyclopentene
e) 3,3-dimethylcyclobutene