vocab ch. 4,5,8 Flashcard

what are two types of stereoisomers?
1-enantiomers
2-diastereomers
constitutional isomers
differ in how atoms are connected to each other, but they have the same molecular formula
stereoisomers
atoms are connected in the same way, but they are in different orientation to each other
What are 2 differences between enantiomers and diasteriomers?
1-enantiomers are mirror images, diastereomers are not.
2-enantiomers have the same physical and chemical properties, while diastereomers have different physical and chemical properties
Regioselective reaction
reaction where two or more constitutional isomers are possible but one predominates
Markonikov’s Rule
the electrophile (H+) adds to the carbon of the alkene that has more hydrogens attached to it
Markonikov’s addition
When an electrophile adds to an alkene following Markonikov’s Rule
Z isomer
same priority on the same side of the molecule
E isomer
Same priority on different sides of the molecule
electrophile
electron loving- it is an atom or molecule that is electron deficient. (has a positive charge)
nucleophile
nucleus loving- atom or molecule that is electron-rich. Can be neutral or negatively charged.
intermediates
molecules or atoms (usually unstable) that are formed in an initial reaction but react further to make the final product
transition state
theoretical state between reactant and intermediate or reactant and product where bonds are in process of being broken & formed
reaction coordinate diagram
diagram showing energy change as progress through tranistion states and intermediates of reaction
what does delta G stand for?
Gibbs Free Energy
What is more favorable, positive or negative delta G?
Negative delta G
activation energy
energy required to move from transition state to the next step
Is the step where delta G is the most positive going to be the slowest or fastest step of the reaction?
Slowest
Catalyst
lowers activation energy and speeds up reaction rate. It may be consumed initially but not regenerated by reaction end
Lindlar Catalyst
metal that adds H, it is weaker than Pd/c and Pt/c catalysts. Can only break a molecule down to an alkene
Pd/c and Pt/C catalysts
metals that add H, stronger than Lindlar. Can break a molecule all the way down to an alkane
Terminal alkyne
Alkyne at the end of a chain. ex: CH3CH2C(triplebond)CH
Internal Alkyne
alkyne not at the end of a chain. No H attached to C(triplebond)C.
Ex: CH3C(triplebond)CCH3
isomers
compounds w/same formula but are not identical
What are the two types of stereoisomers?
1-cis/trans
2-asymmetric centers
asymmetric center
atom bonded to four different atoms or groups
chiral molecule
molecule w/right-handed or left-handed stereoisomers. The molecules mirror image is not the same-they are non-super imposible
Enantiomers
molecules that have 1 asymmetric center and are nonsuperimposible mirror images of each other
R enantiomers
clockwise rotation
S enantiomers
counter clockwise rotation
achiral compounds
-do not have asymmetric centers
-do not rotate polarized light
-optically inactive
Dextrorotary
if light is rotated clockwise; (+) symbol
Levorotary
If light is rotated counter clockwise; (-) symbol
racemic mixture
equal mix of R enantiomers of a compound that is not optically active. Light rotation= 0 degrees
disantiomers
stereoisomers that are not mirror images of each other if more than 1 asymmetric center in the molecule
Meso compounds
-must have 2 or more asymmetric centers
-there will be a plane of symmetry between the 2 asymmetric centers. Each asymmetric center is a mirror image of the other. These compounds do not rotate polarized light because it is super imposible on its mirror image

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