7: Alkenes Structure + Rxn

Question 1

hydrocarbons with C = C

Answer 1

ALKENES

Question 2

what indicates how many rings or double bonds present.

Answer 2

C to H Ratio

Question 3

Degree of Sat: Unsaturated

Answer 3

More pi bonds. C2H6

Question 4

Degree of Sat: Saturated

Answer 4

Less pi bonds. C2H4. Each ring or pi bond removes 2 Hs

Question 5

C = C bond rotation barrier

Answer 5

stereoisomer

Question 6

Multi-substituted C = C. Cis/Trans only good for disubtituted C = C.

Answer 6

E(entgegen) and Z(Zusamamen)

Question 7

E

Answer 7

Opposite sides, Name ex: (E)-2-chloro-2-butene

Question 8

Z

Answer 8

Same sides, Name ex: (Z)-2-Chloro-2-butene

Question 9

Which isomer is the most stable?

Answer 9

Trans (trans rights)

Question 10

More substituted = more stable. Why?

Answer 10

More substitution effects override steric strain.

Question 11

More substituted alkenes. The atomic overlap of C-C bonds with the C=C pi system is stabilizing.

Answer 11

Hyperconjugation

Question 12

why?

Answer 12

Overrides steric strain.

Question 13

Heat is given off when C=C goes to C-C

Answer 13

A more stable alkene gives off less heat. (Start off lower on the energy scale compared to the less stable isomer.)

Question 14

Does trans or cis give less energy when hydrogenated?

Answer 14

Trans

Question 15

Reactive intermediate

Answer 15

Carbocation

Question 16

Products of carbocation rearrangement are…

Answer 16

diestereomer

Question 17

If a product can become more stable,

Answer 17

it will.