Term
| __________ is the study of the three-dimensional structure of molecules. |
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Definition
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Term
| __________ __________ (Structural Isomers) differ in their bonding sequence; their atoms are connected differently. |
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Definition
| 1) Constitutional isomers |
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Term
| __________ have the same bonding sequence, but they differ in the orientation of their atoms in space. |
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Definition
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Term
| Objects that have left-handed and right-handed forms and are non-superimposable are called __________, the Greek word for "handed." |
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Definition
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Term
| We can tell whether an object is __________ by looking at its mirror image. |
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Definition
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Term
| Such objects, such as a chair, a spoon, and a glass of water all look the same in a mirror; they are __________. |
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Definition
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Term
| Two molecules are said to be __________ if they can be placed on top of each other and the three-dimensional position of each atom of one molecule coincides with the equivalent atom of the other molecule. |
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Definition
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Term
| Nonsuperimposable mirror-images molecules are called __________. |
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Definition
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Term
| A __________ compound has always has an enantiomer (a nonsuperimposable mirror image); an __________ compound always has a mirror image that is the same as the original molecule. |
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Definition
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Term
| An __________ or __________ carbon atom is a carbon bonded to four different substituents and is often designated as such by an asterisk. |
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Definition
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Term
| An asymmetric carbon atom is the most common example of a __________ __________, the IUPAC term for any atom holding a set of ligands in a spatial arrangement that is not superimposable on its mirror image. |
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Definition
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Term
| A __________ (or __________ __________) is any atom at which the interchange of two groups gives a stereoisomer. |
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Definition
1) Stereocenter
2) Stereogenic atom |
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Term
| __________ carbons and the __________-bonded carbon atoms in __________-__________ isomers are the most common types of stereocenters. |
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Definition
1) Asymmetric
2) Double
3) cis-trans |
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Term
Test for Chirality:
1) If a compound has no asymmetric carbon atom, it is usually __________.
2) If a compound has just one __________ carbon atom, it must be __________.
3) If a compound as more than one __________ carbon, it may or may not be __________. |
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Definition
1) Achiral
2A) Asymmetric
2B) Chiral
3A) Asymmetric
3B) Chiral |
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Term
| If a molecule lacks an __________ __________ __________, it is often achiral. |
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Definition
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Term
| *Any molecule that has an __________ __________ __________ of symmetry cannot be __________, even thought it may contain asymmetric carbon atoms.* |
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Definition
1) Internal mirror plane
2) Chiral |
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Term
| If a carbon atoms has only __________ different kind of substituents, than it has an internal mirror plane of symmetry and cannot contribute to __________ in a molecule. |
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Definition
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Term
| Any asymmetric carbon has two possible (mirror-image) spatial arrangements, known as __________. |
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Definition
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Term
The __________-__________-__________ __________ is the most widely accepted system for naming the configurations of chirality centers.
Each asymmetric carbon atoms is assigned a letter __________ or __________ based on its three-dimensional configuration. |
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Definition
1) Cahn-Ingold-Prelog Convention
2) (R)
3) (S) |
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Term
When assigning priorities to each group bonded to the asymmetric carbon:
1) Atoms with __________ atomic numbers receive higher priorities.
2) With different isotopes of the same element, __________ isotopes have higher priorities.
3) In case of ties, use the next __________ along the chain of each group as tiebreakers.
4) Treat __________ and __________ bonds as if each were a bond to a separate atom. |
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Definition
1) Higher
2) Heavier
3) Atom
4A) Double
4B) Triple |
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Term
| Mirror-image molecules (enantiomers) have nearly identical __________ properties. |
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Definition
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Term
| __________ is a common method used to distinguish between enantiomers, based on their ability to rotate the plane of polarized light in opposite directions. |
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Definition
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Term
__________-__________ __________ is composed of waves that vibrate in only one plane.
The direction of vibration is called the __________ of the filter. |
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Definition
1) Plane-polarized light
2) Axis |
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Term
| Rotation of the plane of polarized light is called __________ __________, and substances that rotate the plane of polarized light are said to be __________ __________. |
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Definition
1) Optical activity
2) Optically active |
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Term
| Before the relationship between chirality and optical activity was known, enantiomers were called __________ __________ because they seemed identical except for their opposite optical activity. |
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Definition
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Term
| *__________ compounds rotate the plane of polarized light by exactly the same amount but in __________ directions.* |
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Definition
1) Enantiomeric
2) Opposite |
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Term
| *We cannot predict which direction a particular __________ [either (R) or (S)] will rotate the plane of polarized light. |
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Definition
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Term
| A __________ measures the rotation of polarized light. |
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Definition
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Term
| Compounds that rotate the plane of polarized light toward the right (clockwise) are called __________, from the Greek word __________, meaning "toward the right." |
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Definition
1) Dextrorotary
2) Dexios |
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Term
| Compounds that rotate the plane toward the left (counterclockwise) are called __________ from the Latin word __________, meaning "toward the left." |
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Definition
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Term
*Dextrorotatory (clockwise) rotations are __________ or __________.
Levorotatory (counterclockwise) rotations are __________ or __________. |
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Definition
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Term
| The rotation observed in a polarimeter depends on the __________ of the sample solution and the __________ of the cell as well as the __________ __________ of the compound. |
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Definition
1) Concentration
2) Length
3) Optical activity |
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Term
| A compound's __________ __________ [a] is the rotation found using a 10-cm (1-dm) sample cell and a concentration of 1g/ml. The observed rotation should be divided by the path __________ of the cell (l) and the __________ (c). |
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Definition
1) Specific rotation
2) Length
3) Concentration |
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Term
The equation for specific rotation is:
a(observed)/(c x l)
where:
a(observed) = __________ observed in polarimeter
c = __________ in grams per mL
l = __________ of sample cell (path length) in decimeters (dm) |
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Definition
1) Rotation
2) Concentration
3) Length |
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Term
| A __________ __________ is an instrument used to distinguish between enantiomers; a polarimeter serves as one example. |
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Definition
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Term
| __________ in living systems are chiral, and they are capable of distinguishing between enantiomers. |
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Definition
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Term
| A solution of equal amounts of two enantiomers, so that the mixture is optically inactive, is called a __________ __________; it is also called a __________, a (+/-) __________, or a (__________,__________) pair. A __________ __________ is symbolized by placing (+/-) or (d,l) in front of the name of the compound. |
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Definition
1) Racemic mixture
2) Pair
3) Pair
4) d,l
5) Racemic mixture |
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Term
| *A reaction that uses optically __________ reactants and catalysts cannot produce a product that is optically __________. Any __________ product must be formed as a racemic mixture. |
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Definition
1) Inactive
2) Active
3) Chiral |
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Term
When dealing with mixtures that are neither __________ __________ (one enantiomer) nor __________ (equal amounts of two enantiomers) we specify the __________ __________ (o.p.) of the mixture.
__________ __________ is the ratio of its rotation (the o.p. mixture) to the rotation of a pure enantiomer. |
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Definition
1) Optically pure
2) Racemic
3) Optical purity
4) Optical purity |
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Term
| The __________ __________ (e.e.) is a similar method for expressing the relative amounts of __________ in a mixture; to compute e.e., we calculate the excess of the predominant enantiomer as a percentage of the entire mixture. |
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Definition
1) Enantiomeric excess
2) Enantiomer |
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Term
| *A molecule cannot be __________ __________ if its __________ conformations are in equilibrium with their mirror images. We consider such a molecule to be __________.* |
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Definition
1) Optically active
2) Chiral
3) Achiral |
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Term
| *To determine whether a conformationally mobile molecule can be __________ __________, consider its most __________ conformation.* |
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Definition
1) Optically active
2) Symmetric |
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Term
| A molecule cannot be __________ __________ if it is in equilibrium with a structure (or conformation) that is __________. |
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Definition
1) Optically active
2) Achiral |
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Term
| Chrial compounds have NO achievable __________ conformations. |
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Definition
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Term
| When examining whether a molecule is chiral, we should consider cyclohexane rings as if they were __________ (the most __________ conformation) and consider straight-chain compounds in their most symmetric conformations (an __________ conformation). |
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Definition
1) Flat
2) Symmetric
3) Eclipsed |
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Term
| __________ are compounds that contain the C=C=C unit, with two C=C double bonds meeting at a single carbon atom. |
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Definition
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Term
In allene, the central carbon atom is __________ hybridized and __________ and the two outer carbon atoms are __________ hybridized and __________.
The central __________ hybrid carbon atom must use different p orbitals to form the __________ bonds with the two outer carbon atoms. The two unhybridized p orbitals on the __________ hybrid carbon atom are perpendicular, so the two __________ bonds must also be perpendicular. |
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Definition
1) Sp
2) Linear
3) Sp2
3) Trigonal
4) Sp
5) Pi
6) Sp
7) Pi |
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Term
__________ are stereoisomers that are not mirror images.
-__________-__________ isomers, or __________ isomers are two examples of diastereomers. |
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Definition
1) Diastereomers
2) Cis-trans
3) Geometric |
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Term
| Apart from geometric isomers, most other compounds that show __________ have __________ or more chirality centers, usually __________ carbon atoms. |
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Definition
1) Diastereomerism
2) Two
3) Asymmetric |
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Term
*Summary: Types of Isomers*
__________ are different compounds with the same molecular formula.
__________ __________ are isomers that differ in the order in which atoms are bonded together; they are sometimes called __________ __________ because they have different connections among their atoms.
__________ are isomers that differ only in the orientation of their atoms in space.
__________ are mirror-image isomers.
__________ are stereoisomers that are not mirror images of each other.
__________-__________ (__________) __________ are diastereomers that differ in their cis-trans arrangement on a ring or double bond. |
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Definition
1) Isomers
2) Constitutional isomers
3) Structural isomers
4) Stereoisomers
5) Enantiomers
6) Diastereomers
7) Cis-trans (geometric) isomers |
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Term
A compound with n asymmetric carbon atoms has __________ stereoisomers, where n is the number of __________ centers (usually asymmetric carbon atoms).
The __________ rule suggests we look for a maximum of __________ stereoisomers. |
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Definition
1) 2^n
2) Chirality
3) 2^n
4) 2^n |
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Term
| Compounds which are achiral even though they have asymmetric carbon atoms are called __________ __________. |
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Definition
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Term
| *A __________ __________ is an achiral compound that has chirality centers (usually __________ carbons). |
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Definition
1) Meso compound
2) Asymmetric carbons |
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Term
| *__________ __________ is the detailed stereochemnical picture of a molecule, including how the atoms are arranged in space. Alternatively, the (R) or (S) configuration at each __________ center. * |
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Definition
1) Absolute configuration
2) Chirality |
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Term
| When we convert one compound into another using a reaction that does not break bonds at the __________ carbon atom, we know that the product must have the same __________ __________ as the reactant, even if we cannot determine the absolute configuration of either compound. |
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Definition
1) Asymmetric
2) Relative configuration |
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Term
| *__________ __________ is the experimentally determined relationship between the configurations of two molecules, even though we may not know the absolute configuration of either.* |
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Definition
| 1) Relative configuration |
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Term
| __________ have identical physical properties except for the direction in which they rotate __________ __________; __________, on the other hand, generally have different physical properties. |
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Definition
1) Enantiomers
2) Polarized light
3) Diastereomers |
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Term
| Most optically active molecules are found as only one __________ in living organisms. |
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Definition
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Term
The separation of enantiomers is called __________, and it is a different process from the usual physical separations.
A chiral probe is necessary for the __________ of enantiomers; such a chiral compound or apparatus is called a __________ __________. |
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Definition
1) Resolution
2) Resolution
3) Resolving agent |
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Term
| The traditional method for resolving a racemix mixture into its __________ is to use an __________ __________ natural product that bonds with the compound to be resolved. When the enantiomers of the __________ compound bond to the pure __________ __________, a pair of __________ results. |
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Definition
1) Enantiomers
2) Enantiomerically pure
3) Racemic
4) Resolving agent
5) Diastereomers |
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Term
| A carboxylic acid combines with an alcohol to form an __________. |
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Definition
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