November 7 - Energetics

Question 1

Systematic name of an alkene

Answer 1

Replace the -ane at the end of the parent hydrocarbon’s name with -ene

alkene is the double bond functional group

Question 2

Naming a compound with a functional group suffix

Answer 2

1. The longest continuous chain is numbered to give the functional group suffix the lowest possible number
2. For a compound with two double bonds, the “ne” ending is replaced by “diene”
3. Name of substituent is given before the name of the chain that contains the functional group, with a # to indicate the carbon it’s attached to. The functional group suffix gets the lowest # instead of substituents
4. More than one substituent = alphabetical order w/ previous rules for naming
5. If counting in either direction gives the same lowest # for the alkene functional group suffix, the correct name is the one with the lowest substituent number
6. Number not needed for cyclic alkenes

For 1: 2-hexene would signify that the double bond is between the 2nd and 3rd carbons of hexene
For 2: 2,4-heptadiene, 1,3-pentadiene

Question 3

Vinylic carbon

Answer 3

The name for the sp2 carbons in an alkene

Question 4

Allyic carbon

Answer 4

And sp3 carbon that is adjacent to an vinylic (sp2) carbon in an alkene

Question 5

Simple rule for the reactions functional groups undergo

Answer 5

Electron-deficient atoms or molecules are attracted to electron-rich atoms or molecules

Can also be restated as electrophiles react with nucleophiles

p. 153

Question 6

Electrophile

Answer 6

An electron-deficient atom/molecule

“Looks” for a pair of electrons and generally has positive charge

Question 7

Nucleophile

Answer 7

An electron-rich atom/molecule

Has a pair of electrons it can share

Question 8

Reduction reaction

Answer 8

Increases the number of C-H bonds

Question 9

Hydrogenation

Answer 9

The addition of hydrogen

Question 10

Catalytic hydrogenation

Answer 10

Hydrogenation reactions that require a catalyst (all of them do)

Question 11

Choosing the reactant for synthesis in a hydrogenation reaction

From 5.6

Answer 11

Choose an alkene with the same # of carbons and attached in the same way as the desired product

Question 12

Intermediate

in a chemical reaction

Answer 12

A chemical species that is a product of one step of a reaction and a reactant for the next step

Has fully formed bonds (compare w/ transition state)

Question 13

Transition state

in a chemical reaction

Answer 13

Represent the highest energy structures that are involved in a reaction

Have partially formed bonds (compare w/ intermediate)

Exist fleetingly and can’t be isolated

Question 14

Rate-determining/rate-limiting step

Answer 14

In a reaction has two or more steps, the step that has its transition state at the highest point on the reaction coordinate

Basically just the highest peak of potential energy

Question 15

How to draw reaction coordinate diagrams

What do ender, exergonic, intermediate, transition states look like on the graph?

Answer 15

Endergonic = add energy, curve goes upwards
Exergonic = lose energy, curve goes downwards
Intermediate: relative minimum
Transition state: relative maximum

Question 16

Primary, secondary, and tertiary carbocations

Answer 16

Have positive charge on a primary, secondary, and tertiary carbocation, respectively

Question 17

Order of stability for carbocations

Answer 17

From most stable to least stable: tertiary (3°) > secondary (2°) > primary (1°)

Question 18

Hyperconjugation

Answer 18

Delocalization of electrons by the overlap of a σ bond orbital with an empty orbital on an adjacent carbon

Both C and H can overlap for hyperconjugation
6.2 p. 185