ochem

A 1,2-methyl shift occurs when which of the following iodides is heated in ethanol?

(CH3)3CCHICH2CH3

how to solve for formal charge?

(number of valence electrons owned by the isolated atom) - (number of non-bonding electrons on the bound atom) - ( ½ * the number of bonding electrons on the bound atom.

Which Newman projections shows the highest energy conformation of butane?

-highest is the least stable -eclipsed bc force of repulison will be highest and stability least and energy highest

Which sequence of reagents works best to convert 1-bromobutane to hexane?

. NaCN 2. BH3*THF 3. HO-, H2O2

Give the number of asymmetric centers in limonene.

1 bc the carbon atom is attached to four different groups

degress of unsaturation?

1/2[2C+2-H]

What is the approximate value of the indicated bond angle in the following structure?

120 bc, sp2 has trigonal planor shape.

How many asymmetric centers are present in a molecule of 2,4,6-trimethylheptane?

2

what carbocations are likely to rearrange?

2 to 3

Which of the following alkyl bromides is likely to undergo rearrangement by a 1, 2-methyl shift?

2-bromo-3,3-dimethylpentane

Which of the following is capable of exhibiting cis-trans isomerism?

2-butene

How many transition states are present in the following reaction diagram?

2: they are the two peaks on the graph

carbotcation relation to rxn rate of alkene?

2= slow rxn rate with HCl 2=fastest with HBr

Which of the following statements about atomic orbitals is false?

2s orbital are equal in energy is false.

How many asymmetric centers are present in the compound shown below? with two cyclohexanes

3

Which of the following compounds will react most rapidly with HCl?

3 carbotcation bc of stable product. -2-methyl-2-hexene

Which of the following alkyl bromides undergoes solvolysis in methanol without rearrangement?

3-bromo-3-ethylpentane

How many carbons are in the planar double-bond system of 3-methylcyclopentene?

4

How many sigma bonds and how many pi bonds are in ethylene, C2H4?

5 sigma and 1 pi -double bond= 1 single bond besides counting it as a double bond

Which of the following structures correctly represents trans-3-heptene?

7 carbons = between 4 and 3

Which of the following arrow conventions is used to show the relationship of two chemical species as resonance structures?

<-->

Which statement is true in the hydroboration-oxidation of an alkene?

Anti-Markovnikov orientation and syn addition occur.

leaving group

Atoms or groups that can dissociate from the parent chain to form a stable species after accepting electron pairs. Weak bases tend to be good leaving groups.

Which of the following solvents is protic?

CH3CH2OH all alcohols are protic

Which of the following is not an electrophile?

CH3COCH3

Which of the following reagents are required to form CH3Br?

CH3OH + HBr

How to solve degree of unsaturation?

DoU= (2C+2+N-X-H)/ 2 C=# of carbons N= #of nitrogens X= # of halogens H= # of hydrogens

Which of the following is not a nucleophile?

FeBr3

Identify the compound(s) with asymmetric centers.?

H--C(TOP IS Cl) and (BOTTOM IS CH2CH2CH3)--CH(CH3)2

Which of the following structures is the best Lewis structure for hypochlorous acid, HOCl?

H-O::-Cl:::

Which of the following is the most acidic hydrocarbon?

H-triple bond-CH3 BC ACIDIC CHARACTER INcreases is % s hyberdization

Which of the following pairs are not related as resonance structures?

H3C--C(connected to OH) ==CH2 and H3C--C(double bond O)--CH3

Which of these structures represent the same compound?

I-a four carbon that has methylbondCl on number 2 carbon L->R II-Cl--C-(CH3-H up and down)-C-(H-H up and down)--CH3

Which statement is true in the oxymercuration-reduction of an alkene?

Markovnikov orientation and syn addition occur

QQ: Is hypochlorous acid, HOCl, a strong acid? Why?

No. The conjugate base is stable

Which of the following reagents can be used to convert methyl alcohol to methyl chloride?

SOCl2, pyridine

Why is the alkyl halide below not capable of undergoing an E2 reaction upon treatment with sodium ethoxide?

The C-H and C-Br bonds which need to break cannot achieve an anti-periplanar orientation.

Which of the following Lewis structures shows an incorrectly drawn bond dipole?

The arrows have to be pointing to the more electronegative.

According to the Hammond Postulate, which of the following is correct?

The transition state of an exothermic reaction step will be more reactant-like than product-like.

Which of the following correctly describes intermediates and/or transition states?

Transition states have partially formed bonds whereas intermediates have fully formed bonds.

what does it mean to exhibit chirality?

a carbon with four bonds with H being 4. CH3 being 3 -2,3-dibromobutane -1,3-dibromobutane -1,4-dibromobutane

protic

a solvent with a hydrogen attached to a highly electronegative atom

Which of the following compounds has an asymmetric center?

assymetric: c bonded to four different bonds

Give the possibilities in structure for a compound with a formula of C6H6.

benzene: 3 double bonds and 1 ring

Which of these bases can deprotonate acetylene (pKa 26)? The pKa values for the conjugate acids are shown in parentheses

butyllium (50-60) and NaNH2(36)

Identify the pair of compounds.? they were mirror images

configurational isomer

What type of isomers are CH3CH2OCH3 and CH3CH2CH2OH?

constitutional isomers (structural)what

Which of the following structures is in the gauche butane conformation?

dashed: forward(comes forward out of the plane of page) wedged: backwards(goes backwards or behind the plane of paper)

What is the relationship between the following compounds? one is trans and other cis

diastereomers=> configurational

constitutional isomers?

differ in the order of attachment of atoms -same molecular formula but the connectivity is different

aprotic?

doesnt have H attached to electronegative atom

A and B are stereoisomers. They are nonsuperimposable and are mirror images of one another. Which of the following best describes the relationship between A and B?

enatiomers

What is the relationship between the structures shown below? (set 2 Q16)

identical bc both are R

structural isomers (constitutional isomers)?

molecules that have the same molecular formula but differ in the way the atoms are connected

Which of the following compounds is an enantiomer of the structure below? s2q17

no enatiomer

Enatiomers?

non super imposable mirror images

Which of the following molecules has a net dipole moment? -What does it mean to have net dipole moment?

none: when all arrows go out of the middle element net dipole: when all arrows point towards the middle atom.

Which of the following is the best reaction sequence to use if one wants to accomplish a Markovnikov addition of water to an alkene with minimal skeletal rearrangement?

oxymercuration-reduction

When (R)-2-butanol reacts with TsCl in pyridine, the product obtained is

single enantiomer

What atomic orbitals are involved in the formation of the sigma bond between the two carbons indicated in this structure?

sp2 and sp3 -count the number of bonds that carbon has then, subtract 1

carbocation stability trend

tertiary > secondary > primary > methyl

Which of the following statements correctly describes the molecule shown below? s2q18

the mirror of this molecule is its enantiomer

Which of the following Newman projections shows a dihedral angle of 60° between HA and HB?

think as if the Ha never moves but the Hb will move clockwise;imagine where the degrees will be on an actual circle and build on that.

Which of the following compounds is chiral?

top to bottom H--CH3(left)--Br(right)---CH3(left)--Cl(right)--H

Which of the following solvents is aprotic?

trans-1,2-dimethylcyclohexane

Each of the chemical events shown represents a mechanistic step in a reaction you will learn this semester. Which of the following pictures represents the heterolytic cleavage of a carbon-oxygen bond?

where the bond from C attacks O:+