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1 | | What is the relationship between 1-butene and cis-2-butene? |
| | A) | unrelated compounds |
| | B) | constitutional isomers |
| | C) | enantiomers |
| | D) | diastereomers |
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2 | | What is the relationship between trans-2-butene and cis-2-butene? |
| | A) | unrelated compounds |
| | B) | constitutional isomers |
| | C) | enantiomers |
| | D) | diastereomers |
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3 | | Determine the relationship between the two molecules shown. (16.0K) |
| | A) | constitutional isomers |
| | B) | enantiomers |
| | C) | diastereomers |
| | D) | identical molecules |
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4 | | Determine the relationship between the two molecules shown.
(14.0K) |
| | A) | constitutional isomers |
| | B) | enantiomers |
| | C) | diastereomers |
| | D) | identical molecules |
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5 | | Give all terms that describe compounds (a) and (b). (16.0K) |
| | A) | enantiomers |
| | B) | diastereomers |
| | C) | same compound |
| | D) | chiral molecules |
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6 | | How many stereoisomers are there for the following structure? (11.0K) |
| | A) | 1 |
| | B) | 2 |
| | C) | 3 |
| | D) | 4 |
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7 | | Which of the following molecules exists as a pair of enantiomers? |
| | A) | 2-Bromopropane |
| | B) | 1-Bromo-3-methylbutane |
| | C) | 2-Cyclohexen-1-ol |
| | D) | cis-1,2-Dichlorocyclobutane |
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8 | | Which of the following diols exists as a pair of enantiomers? |
| | A) | cis-1,3-Cyclohexanediol |
| | B) | trans-1.3-Cyclohexanediol |
| | C) | cis-1,4-Cyclohexanediol |
| | D) | trans-1,4-Cyclohexanediol |
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9 | | Which of the following is capable of existing as a pair of enantiomers? |
| | A) | 2-methylpropane |
| | B) | 2-methylpentane |
| | C) | 3-methylpentane |
| | D) | 3-methylhexane |
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10 | | Which of the 7 isomers of dichlorocyclohexane possess a plane of symmetry? |
| | A) | cis-1,2; cis-1,3; |
| | B) | 1,1; cis-1,2; cis-1,3; |
| | C) | cis-1,2; cis-1,3; cis-1,4; |
| | D) | 1,1; cis-1,2; cis-1,3; cis-1,4; trans-1,4 |
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11 | | Which of the following has a plane of symmetry? |
| | A) | cis-1,2-Dimethylcyclohexane |
| | B) | trans-1,3-Dimethylcyclohexane |
| | C) | 1,3-Dimethylcyclohexene |
| | D) | 1,4-Dimethylcyclohexene |
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12 | | What is the IUPAC name of the following molecule? (13.0K) |
| | A) | (3R,5S)-dibromohexane |
| | B) | (2R,4R)-dibromohexane |
| | C) | (2R,4S)-dibromohexane |
| | D) | (R,S)-dibromohexane |
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13 | | Which of the following groups has the highest priority in the (R,S) system? |
| | A) | (10.0K) |
| | B) | –CH=CH2 |
| | C) | –CH2–CH3 |
| | D) | (12.0K) |
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14 | | What is the correct name for this molecule? (15.0K) |
| | A) | (2R,3R)-2-bromo-3-chlorobutane |
| | B) | (2S,3R)-2-bromo-3-chlorobutane |
| | C) | (2S,3S)-2-bromo-3-chlorobutane |
| | D) | (2R,3S)-2-bromo-3-chlorobutane |
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15 | | The respective configurations of a and b are: (14.0K) |
| | A) | (2R,3S) and (2R,3R) |
| | B) | (2S,3R) and (2S,3R) |
| | C) | (2S,3S) and (2R,3R) |
| | D) | (2S,3R) and (2S,3S) |
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16 | | What is the specific rotation 20[α
]D of the following molecule? (18.0K) |
| | A) | +4.42o |
| | B) | +0.442o |
| | C) | +44.2o |
| | D) | – 44.2o |
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17 | | Which of the following physical properties differ for each of a pair of enantiomers? |
| | A) | solubility in ethanol |
| | B) | direction of rotation of plane-polarized light |
| | C) | boiling point and melting point |
| | D) | index of refraction |
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18 | | An optically active compound is composed of 75% of the (R) enantiomer and 25% of the (S) enantiomer. The enantiomeric excess (ee) is equal to |
| | A) | 87.5%. |
| | B) | 75%. |
| | C) | 50%. |
| | D) | 37.5%. |
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19 | | If a sample of 2-butanol has an enantiomeric excess of 60% of l-2-butanol, how much of each isomer is present? |
| | A) | 60% levorotatory and 40% dextrorotatory |
| | B) | 80% levorotatory and 20% dextrorotatory |
| | C) | 70% levorotatory and 30% dextrorotatory |
| | D) | 66% levorotatory and 34% dextrorotatory |
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20 | | How many stereocenters are there in the following molecule? (17.0K) |
| | A) | 0 |
| | B) | 2 |
| | C) | 3 |
| | D) | 1 |
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21 | | Which of the following statements is TRUE? |
| | A) | To be diastereomers, a pair of molecules must have 2 or more chiral centers. |
| | B) | To be diastereomers, a pair of molecules must have at least 1 chiral center. |
| | C) | To be diastereomers, a pair of molecules must be stereoisomers. |
| | D) | To be diastereomers, a pair of molecules must be a racemate. |
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22 | | Shikimic acid is an important natural product. How many stereoisomers are possible for shikimic acid? (15.0K) |
| | A) | 16 |
| | B) | 8 |
| | C) | 4 |
| | D) | 2 |
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23 | | Consider the following two structures. What is their isomeric relationship to each other? (16.0K) |
| | A) | identical |
| | B) | enantiomers |
| | C) | diastereomers |
| | D) | constitutional isomers |
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24 | | Explain why the two stereoisomers of 1,4-dimethylcyclohexane are achiral? (14.0K) |
| | A) | because they are identical |
| | B) | because they are enantiomers |
| | C) | because they both have the same absolute configuration |
| | D) | because there are no stereocenters present in either molecule |
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25 | | How many stereoisomers are there for 1-ethyl-3-methylcyclohexane?
(12.0K) |
| | A) | 2 |
| | B) | 3 |
| | C) | 4 |
| | D) | 6 |
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26 | | What is the relationship between (1R,2S)-dibromocyclohexane and (1S,2R)-dibromocyclohexane? |
| | A) | identical |
| | B) | enantiomers |
| | C) | diastereomers |
| | D) | constitutional isomers |
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27 | | What is the relationship between (1R,2S)-1-bromo-2-methylcyclohexane and (1S,2R)-1-bromo-2-methylcyclohexane? |
| | A) | identical |
| | B) | enantiomers |
| | C) | diastereomers |
| | D) | constitutional isomers |
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28 | | Which of the following may be separated by ordinary physical methods? |
| | A) | a pair of identical molecules |
| | B) | a pair of enantiomers |
| | C) | a pair of diastereomers |
| | D) | a pair of identical atoms |
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29 | | Which of the following may be separated by ordinary physical methods? |
| | A) | (R)-3-bromo-1-butene and (S)-3-bromo-1-butene |
| | B) | cis-2-bromo-2-butene and trans-2-bromo-2-butene |
| | C) | (2R,3S)-1,2-dibromobutane and (2S,3R)-1,2-dibromobutane |
| | D) | (R)-2-bromobutane and (S)-2-bromobutane |
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30 | | Consider the following two stereoisomers. How are they different? (13.0K) |
| | A) | They have different melting points. |
| | B) | They rotate plane-polarized light in opposite directions. |
| | C) | They have different solubilities in water. |
| | D) | They have different indices of refraction. |
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