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36 Cards in this Set
- Front
- Back
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Enantiomer
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Enantiomer: A molecule that cannot be superimposed on its mirror image.
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A molecule that cannot be superimposed on its mirror image.
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Enantiomer
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Chirality
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Chirality: "Handedness"
- Chiral or achiral |
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What is a "chiral" molecule? There are two definitions.
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Chiral Molecule:
- A molecule that has either left or right handedness. - (formal definition) A molecule that is not superimposable on its mirror image. |
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A molecule that has either left or right handedness.
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A chiral molecule.
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Achiral
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Achiral: A molecule that has an internal plane of symmetry.
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What is a "constitutional isomer"?
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Constitutional isomer:
- Same molecular weight - Same atoms - Different bonding |
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What type of isomer has the following three characteristics?
- Same molecular weight - Same atoms - Different bonding |
Constitutional isomer
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What is a stereoisomer?
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Stereoisomer: Molecules that vary only in 3D orientation.
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What type of molecule can be described as follows:
Molecules that only vary in 3D orientation. |
Stereoisomers: Molecules that vary only in 3D orientation.
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What is an asymmetric carbon?
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Asymmetric carbon: A carbon atom bound to four different things.
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What is a chiral molecule?
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Chiral molecule: A molecule that is not identical to its mirror image.
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Can molecules have chiral centers but be achiral overall?
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Yes, these are called "miso compounds".
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Miso compounds
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A molecule that has chiral centers along with an internal plane of symmetry.
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How are asymmetric centers described in organic chemistry?
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Asymmetric centers are described using "R" and "S" within the molecule's name.
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What do you do after assigning "R" and "S" to the molecule?
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After assigning "R" and "S" to a molecule, one determines its 3D orientation.
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How do you rank double and triple bonds in stereochemistry?
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Think about double and triple bonds as "expanded" (i.e. as if they're all bonded atoms are separate).
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Does a chiral molecule have an internal plane of symmetry?
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No, a chiral molecule does not have an internal plane of symmetry.
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True or false?
A chiral molecule does not have an internal plan of symmetry. |
True.
A chiral molecule does not have an internal plane of symmetry. |
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True or false?
A chiral molecule has an internal plane of symmetry. |
False.
A chiral molecule does not have an internal plane of symmetry. |
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Rank the following atoms from heaviest to lightest:
H, N, P, S, Cl, O, Br, C |
Br, Cl, S, P O N, C, H
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A molecule with "n" chirality centers can generally have up to __ stereoisomers.
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A molecule with "n" chirality centers can generally have up to 2^n stereoisomers.
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Diastereomers
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Diastereomers: Isomers that are not mirror images.
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What is the terms for isomers that are not mirror images of one another?
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Diasteromers: Isomers that are not mirror images.
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What is the difference between enantiomers and diasteromers?
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Enantiomers have chirality at all centers.
Diastereomers have chirality at one or several centers, but not all of the molecule's centers. |
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Epimer
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Compounds are "epimers" when they differ in only one center and are the same at all other centers.
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Name the three types of stereoisomers.
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Four types of stereoisomers:
- Enantiomers - Diastereomers - Cis-Trans isomers |
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Describe a prochiral molecule.
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A prochiral molecule is a molecule that can be converted from achiral to chiral in a single step.
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A ____________ molecule is a molecule that can be converted from achiral to chiral in one step.
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A prochiral molecule is a molecule that can be converted from achiral to chiral in one step.
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Can sp3 hybridized atoms be prochiral?
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Yes.
sp3 hybridized atoms can be prochiral. |
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What is used to describe optical rotation within prochiral sp2 hybridized atoms?
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Re = clockwise <-- akin to R rotation
Si = counterclockwise <-- akin to S rotation |
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What is the deal with pro-R and pro-S atoms?
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One gets pro-R or pro-S atoms when the atom is prochiral and its rotation is changed to either the R or S rotation.
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Out of the two, which have the same physical properties? Which one has different physical properties?
- Enantiomers - Diasteromers |
Enantiomers have the same physical properties.
Diasteromers have different physical properties. |
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Define optical polarity. What is its symbol?
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Optical polarity: The observed optical rotation of plane polarized light shined on a mixture of a certain molecule.
Symbol: [alpha]0 |
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When optical polarity equals zero, what two types of molecules might you have?
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- Meso compound
- Achiral molecule |
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When optical polarity doesn't equal zero, what type of molecule do you have?
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When optical polarity doesn't equal zero, the type of molecule in the mixture is a chiral molecule.
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