Term
| name the 3 important hybrid orbitals and their respective geometries |
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Definition
sp-180* linear
sp2- 120* trigonal planar
sp3-109.5* tetrahedral, pyrimidal, or bent |
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Term
what is the difference between sigma and pi bonds?
which is more stable?
explain rigidity in molecular structure. |
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Definition
sigma bonds- strongest because the most stable. bind at plan of the atom's nuclei. free rotation about axis.
pi bonds- above of below the plane of the nuclei, less stable; more reactive, fixed rotation. |
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Term
| what does vsepr stand for? be able to predict the shapes of molecules based on this. |
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Definition
valence shell electron pair repulsion.
AX- LINEAR
AX2- bent, etc |
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Term
| Where are delocalized electrons located in resonance of ions and molecules? |
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Definition
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Term
| what is imp to remember in drawing resonance structures? |
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Definition
| electrons are moved, not atoms |
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Term
| In regards to multiple bonding how does it effect bond length and strength. |
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Definition
bond length of c-c>c=c
bond strength of c-c
same relationship exists with all bonds |
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Term
structural isomers aka ______
and define it. |
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Definition
constitutional isomers
same molecular formular difference in bonding of atoms |
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Term
define stereoisomers:
what are some examples of them? |
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Definition
same molecular formula and same bond to bond of atoms
diastereomers, enantiomers, cis and trans isomers, etc |
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Term
conformational isomers are?
how does one discern between the two? |
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Definition
| not true isomers and have different spatial orientations. Distinguished via newman projections. |
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Term
polarized light is ___
what are the directions? |
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Definition
light going in the same direction.
[cw + d ]
[ccw - l]
cannot be determinied based on absolute or relative configuration |
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Term
| what is the difference between absolute and relative configuration? |
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Definition
absolute configuration- determines the orientation of atoms about a chiral center. Lowest priority atoms are placed in the back or the direction is reversed.
R-CW....... S-CCW
relative configuration- inverted during SN2 reactions. molecules have the same orientation of atoms about a chiral center except for one substituent. |
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Term
what are racemic mixtures?
how does one separate enantiomers? |
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Definition
50% diastereomers 50% enantiomers. they don't rotate plane polarized light.
separation of enantiomers by resolution. |
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Term
| Discuss the physical properties of alkanes |
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Definition
Increase Molecular Weight; increase boiling point and melting point. branching is unfavorable.
increase m.w with polar group attached decreases the solubility.
soluble in nonpolar substances.
low densities (oil floats on water) |
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Term
Important reactions of ALKANES:
(Radical reactions)
Discuss Combustion and Halogenation. |
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Definition
Combustion :
alkane + Oxygen gas -> CO2+H20 + heat.
Halogenation :
3 steps : initiation, propagation, termination.
stability: 3*>methyl |
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Term
| how does ring strain affect cyclic compounds? |
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Definition
makes them more reactive since strain is unfavorable outside the cyclohexane circumstance.
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Term
| Look up nomenclature on alchols, alkanes, acids, etc |
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Definition
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Term
| what are some electron withdrawing groups? |
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Definition
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Term
| What are some electron donations groups? |
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Definition
| anything with a partial + charge on the bonding atom. And halogens. |
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Term
Nucleophilicity:
if a nucleophile behaves as a base what happens?
what is the periodic trend for it?
it doesnt phase a (SN1/SN2) reaction. |
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Definition
elimination occurs
it decreases going up and to the right
SN1 |
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Term
SN1 vs SN2
1) a strong nucleophile is required for?
2)How does steric effect affect SN1 and SN2 rxns.
3) polar solvents increase the rate of reaction of (SN1/SN2) reactions by? and does what to the other reaction.
4)the speed of an SN2 reaction depends on the ___ while an SN1 reaction depends on the ___.
5) what does each reaction do to the stereochemistry? |
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Definition
1)SN2 rxn
2) Sn1 secondary and tertiary subtrates- for a stale carbocation. while a sn2 reaction needs a less hindered substrate because of nucleophilic attack.
3) Increases sn1 reaction by stabilizing the carbocation, slows sn2 by stabilizing the nucleophile.
4) concentration of the substrate and nucleophile; concentration of the substrate.
5 SN1- racemic mixture with possible carbocation rearrangement, SN2- inversion of chiral center |
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Term
| physical properties of ALCOHOLS |
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Definition
higher BP because of hydrogen bonding, and higher solubilities than alkanes.
tertiary alcohol more basic then primary alcohol. |
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