CHEM 230 Final Exam Questions and Answers Graded A+
IR Spectra - Answers -Absorption of radiation causes vibrational excitation of functional groups
*making it easy to ID functional groups*
*0-5000cm-1*
H NMR Spectra - Answers *0-12ppm*
C NMR Spectra - Answers *0-200ppm*
Mass Spec - Answers -Used to measure the molecular weight (mass) of the compound.
Alkyne Reactions - Answers *1* Alkyne + H2/Pd &C = Alkene
*2* Alkyne + H2/Lindlav Cat.= Cis Alkene
*3* Alkyne + Li or Na/Liquid NH3= Trans Alkene
*4* Alkyne + (HBr/HCL & Br2)= Alkene with X on same C
*5* Alkene + H20= Alkene (enol-->ketone)
Carbocation General Info. - Answers -Sp2 hybridization
-Empty P orbital
-Stereochemistry: Flat and can be attacked on top or bottom *Non-stereoselective*
Nucleophile Vs. Electrophile - Answers *Nucleophile* :
-Electron *rich*
- *Anion* , lone pair, etc.
*Electrophile* :
-Electron *deficient*
- *Cation* , + side of ion, empty orbitals
Stereoselectivity - Answers - *Stereoselective*
(either syn/anti addition)
, - *Non-Stereoselective*
(Differ Intermediates formed/ Racemic Mix)
Meso Compound - Answers -Line of sym. present within compound
*Achiral*
Regioselectivity - Answers *Markovnikov's* Rule:
- *H+ initially attacks more stable/substit. C.*
*Anti-Markovnikov's* Rule:
- *H+ initially attacks more stable/substit. C.*
Markovnikov's Rule (Regioselectivity) - Answers Addition of HX;H2O;ROH to an alkene.
H + the carbon of double bond w greater # of H.
Hammond Postulate (Regioselectivity) - Answers 2 competing pathways for mech:
-Intermediate *less Ae needed to initiate* (more stable/substit) forms faster --> *Major Product*
-Intermediate *MORE Ae needed to initiate* (less stable/substit) forms slower--> *Minor
Product*
All Alkene Reactions Overview - Answers *Electrophilic Additions*
1. Addition of Hydrogen Halides (Hx)
2. Acid-Catalyzed Hydration (H20)
3. Oxymercuration-Reduction
4. Hydroboration-Oxidation
5.Catalytic Reduction (Hydrogena.) Alkene
Electrophilic addition of Hx->Alkenes *Know Mech* - Answers 1. Electrophile (substrate): *Hx*
2. Reagents: *NONE*
IR Spectra - Answers -Absorption of radiation causes vibrational excitation of functional groups
*making it easy to ID functional groups*
*0-5000cm-1*
H NMR Spectra - Answers *0-12ppm*
C NMR Spectra - Answers *0-200ppm*
Mass Spec - Answers -Used to measure the molecular weight (mass) of the compound.
Alkyne Reactions - Answers *1* Alkyne + H2/Pd &C = Alkene
*2* Alkyne + H2/Lindlav Cat.= Cis Alkene
*3* Alkyne + Li or Na/Liquid NH3= Trans Alkene
*4* Alkyne + (HBr/HCL & Br2)= Alkene with X on same C
*5* Alkene + H20= Alkene (enol-->ketone)
Carbocation General Info. - Answers -Sp2 hybridization
-Empty P orbital
-Stereochemistry: Flat and can be attacked on top or bottom *Non-stereoselective*
Nucleophile Vs. Electrophile - Answers *Nucleophile* :
-Electron *rich*
- *Anion* , lone pair, etc.
*Electrophile* :
-Electron *deficient*
- *Cation* , + side of ion, empty orbitals
Stereoselectivity - Answers - *Stereoselective*
(either syn/anti addition)
, - *Non-Stereoselective*
(Differ Intermediates formed/ Racemic Mix)
Meso Compound - Answers -Line of sym. present within compound
*Achiral*
Regioselectivity - Answers *Markovnikov's* Rule:
- *H+ initially attacks more stable/substit. C.*
*Anti-Markovnikov's* Rule:
- *H+ initially attacks more stable/substit. C.*
Markovnikov's Rule (Regioselectivity) - Answers Addition of HX;H2O;ROH to an alkene.
H + the carbon of double bond w greater # of H.
Hammond Postulate (Regioselectivity) - Answers 2 competing pathways for mech:
-Intermediate *less Ae needed to initiate* (more stable/substit) forms faster --> *Major Product*
-Intermediate *MORE Ae needed to initiate* (less stable/substit) forms slower--> *Minor
Product*
All Alkene Reactions Overview - Answers *Electrophilic Additions*
1. Addition of Hydrogen Halides (Hx)
2. Acid-Catalyzed Hydration (H20)
3. Oxymercuration-Reduction
4. Hydroboration-Oxidation
5.Catalytic Reduction (Hydrogena.) Alkene
Electrophilic addition of Hx->Alkenes *Know Mech* - Answers 1. Electrophile (substrate): *Hx*
2. Reagents: *NONE*
