Question 1

Which of the following is the correct IUPAC name for the compound with the following structure: a seven-carbon chain with methyl groups at carbons 2, 5, and 5, and a sec-butyl group at carbon 4?

Accepted Answer

4-sec-butyl-2,5,5-trimethylheptane

Question 2

Given the Newman projection of ethane looking down the C–C bond, which conformation is the most stable?

Accepted Answer

Staggered conformation

Question 3

Which of the following statements about chair conformations of cyclohexane is TRUE?

Accepted Answer

The most stable chair conformation places bulky substituents in the equatorial positions.

Question 4

How many possible stereoisomers exist for a compound with 3 chiral centers and no internal plane of symmetry?

Accepted Answer

$$2^3 = 8$

Question 5

A compound has a specific rotation of $$-16.31^\circ. $$What is the specific rotation of its enantiomer?

Accepted Answer

$$+16.31^\circ$$

Question 6

Which of the following pairs of compounds are enantiomers?

Accepted Answer

Two molecules that are non-superimposable mirror images of each other

Question 7

Which of the following best describes a meso compound?

Accepted Answer

A compound with chiral centers and an internal plane of symmetry, making it achiral

Question 8

Which of the following statements about reaction energy diagrams is correct?

Accepted Answer

A reaction with a positive $$\Delta G is $$endergonic

Question 9

Which of the following is the correct assignment for the configuration of a chiral center with the following priorities: Br \u003e OH \u003e CH$$_3$$ \u003e H, with H pointing away and the sequence Br → OH → CH$$_3$$ proceeding clockwise?

Accepted Answer

(R)

Question 10

Which of the following best describes a nucleophile?

Accepted Answer

A species that donates an electron pair to form a new covalent bond

Question 11

Which of the following carbocations is the most stable?

Accepted Answer

A tertiary carbocation

Question 12

Which of the following statements about the thermodynamic and kinetic control of reactions is TRUE?

Accepted Answer

The thermodynamically favored product is the one with the lowest free energy ($$\Delta G)$$

Question 13

Which of the following is a correct statement about molecular collisions in chemical reactions?

Accepted Answer

Some molecular collisions do not result in a reaction

Question 14

Which of the following best describes the (E) configuration of an alkene?

Accepted Answer

The two highest priority groups are on opposite sides of the double bond

Question 15

A mixture of two enantiomers has a specific rotation of $$+7.54^\circ. If $$the pure enantiomers have specific rotations of $$+16.31^\circ$$ and $$-16.31^\circ$$, which enantiomer is in excess?

Accepted Answer

The enantiomer with $$+16.31^\circ$$ specific rotation

Question 16

Which of the following transformations involves a carbocation rearrangement?

Accepted Answer

A hydride shift from a secondary to a tertiary carbon after loss of a leaving group

Question 17

Which of the following is the correct classification for the following pair of compounds: same molecular formula, different connectivity?

Accepted Answer

Constitutional isomers

Question 18

Which of the following is TRUE regarding the specific rotation of a racemic mixture?

Accepted Answer

The specific rotation is $$0^\circ$$

Question 19

Which of the following best describes the arrow-pushing pattern in a nucleophilic substitution reaction (S$$_N2$$)?

Accepted Answer

Nucleophilic attack and loss of a leaving group occur simultaneously

Question 20

Which of the following is the correct relationship between the rate of a reaction and the activation energy ($$E_a$$)?

Accepted Answer

A higher activation energy corresponds to a slower reaction rate

Organic Chemistry Exam 2 Study Guidance

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