Organic Chemistry Flashcards
(37 cards)
True or false, the longer the chain length, the higher the boiling point, melting point, and density.
True
True or false, the more branching a carbon chain has, the higher the boiling point, melting point, and density.
False
What does meso mean?
That a molecule with two chiral centers has a plane of symmetry in it. Also, that molecule is superimposable.
What are diastereomers?
Types of stereoisomer that are superimposable.
What are enantiomers?
Stereoisomers that are superimposable.
A single bond has a ____ bond length and a ____ bond energy than a double or triple bond.
Longer, Lower
In the cyclohexane boat configuration, where are substituents preferred to be?
In the equatorial position.
Are meso compounds optically active?
No
What are racemic mixtures?
Mixtures with an even number of R and S chiral centers. There is no optical activity.
Conformational isomers are associated with Newman projections, true or false?
True.
Describe the initiation, propagation, and termination steps in free radical halogenation.
- Initiation: Heat is applied to a diatomic halogen forming two free radical halogens.
- Propagation: One of the free radicals pulls a Hydrogen off an alkane while the other reactions with the carbon forming RX.
- Termination: Two free radicals react and form a diatomic halogen.
Which carbocations are the most stable? Which free radicals are the most stable?
Tertiary carbocations and Tertiary free radicals (•CR3)
Name the five Electrophilic aromatic substitution reactions.
Halogenation Sulfonation Nitration Alkylation Acylation
What’re vicinal and geminal diols?
Vicinal diols are two alcohols on two separate carbons. Geminal means two alcohols on the same carbon.
E1
Unimolecular, 2 step, elimination reactions where the rate is dependent upon the substrate. The LG is eliminated forming a carbocation and a Beta proton is removed by a base to form an alkene. Requires polar solvents, good leaving groups, and favors high temperatures.
E2
Bimolecular, 1 step, elimination reactions where the rate is dependent upon the substrate and the base. The Base removes a beta proton that is antiperiplanar to the halogen while the halogen is removed simultaneously. The more substituted alkene is preferred.
SN1
Unimolecular, 2 step, nucleophilic substitution reaction where the rate is dependent upon the substrate. This is favored in protic solvent, it gives racemic products, and prefers more substituted electrophiles.
SN2
Bimolecular, 1 step, nucleophilic substitution reaction where the rate is dependent upon the substrate and the nucleophile. A strong nucleotide attacks the molecule from the backside releasing the LG and inverting the stereochemistry. This favors aprotic solvents and unhindered molecules.
What is the general formula for the amount of carbons and hydrogens on an alkane chain, alkene chain, and alkyne chain?
Alkane = C(n) H(2n+2)
Alkene = C(n) H(2n)
Alkyne = C(n) H(2n-2)
where n is the number of Carbon atoms.
What is the formula for the degree of unsaturation?
Number of double bonds = 1/2 (2n+2-m) where n is the number of carbons and m is number of hydrogens.
What factors determine a good nucleophile?
- Charge-the more negative, the better.
- Electronegativity-In protic solvents, the the more electronegative the nucleophile, the worse. In aprotic, the more electronegative, the better.
- Sterics-the more bulky a nucleophile, the slower the rate of reaction.
Do EWG or EDG’s make something more acidic? Why?
EWG make a molecule more acidic because it increases the range of electron delocalization.
What are ortho/para activators, ortho/para deactivators, and meta deactivators?
o/p activators are EDG such as -OCH3, -OH, and -NH2 that increase the rate of reaction.
o/p deactivators are EWG halogens that decrease the rate of reaction.
meta deactivators are EWG such as -NO2, -COOH, and -CN that also decrease the rate of reaction.
What factors determine a good leaving group?
Weak bases (or conjugate bases) such as H20, HSO4, Br, Cl, I, and the conjugate base of tosic acid.
