#3: Alknenes and Cycloalkenes

Question 1

aliphatic hydrocarbons whose molecules contain double-bond carbon-carbon atom.

Answer 1

alkenes

Question 2

the old name of alkenes that is still often used

Answer 2

olefins

Question 3

the simplest olefin (alkene), was called olefiant gas

Answer 3

Ethene (ethelene)

Question 4

• the lowest form of alkene is planar angles between bonds are 120 degrees
  -It is sp2 hybrid Orbital

Answer 4

ethene

Question 5

The molecular formula of alkenes

Answer 5

CnH2n

Question 6

is an orbital formed by the linear combination of one s and two p orbitals of comparable energy (such 2s and 2p orbitals) on the same atom.

Answer 6

sp2 orbital

Question 7

covalent chemical bonds, in each of which two lobes of an orbital on one atom overlap with two lobes of an orbital on another atom, and in which this overlap occurs laterally.

Answer 7

pi bond

Question 8

Covalent bonds are formed by the ______ of atomic orbitals.

Answer 8

overlapping

Question 9

a result of the head-to-head overlapping of atomic orbitals

Answer 9

sigma bond

Question 10

what kind of bond is a single carbon-carbon bond

Answer 10

sigma bond

Question 11

5. If more than one double bond is present, indicate their position by using the number of the first carbon of each double bond and use the suffix ____ (for 2 double bonds), _____ (for 3 double bonds), and _____ (for 4 double bonds)

Answer 11

-diene; -triene; tetraene

Question 12

alkenes have a double bond at the end of the carbon chain.

Answer 12

terminal alkenes

Question 13

have at least one carbon atom bonded to
end of the double bond.

Answer 13

internal alkenes

Question 14

A carbon-carbon triple bond consists of ____ and _____

Answer 14

one sigma bond; two π bonds

Question 15

contain a double bond in a ring.

Answer 15

cycloalkenes

Question 16

Alkenes are ____ than water and are _____ in water due to their ____ characteristics. Alkenes are only ____ in nonpolar solvents.

Answer 16

less dense; insoluble; non-polar; soluble

Question 17

Alkenes are prepared (synthesized) industrially by ____ of petroleum.

Answer 17

thermal cracking

Question 18

a reaction that literally cracks or breaks alkane into smaller ones.

Answer 18

cracking

Question 19

alkenes can be prepared from alkyl halides and alcohols via ____.

Answer 19

elimination reactions

Question 20

a plant hormone that induces ripening of fruits.

Answer 20

ethene

Question 21

a reaction in alkenes where the π bond is broken and two new σ bonds are formed.

Answer 21

addition reaction

Question 22

Alkenes are _____, with the electron density of the π bond concentrated above and below the plane of the molecule.

Answer 22

electron-rich

Question 23

Alkenes react with ____.

Answer 23

electrophiles

Question 24

takes place when both X and Y are added from the same side.

Answer 24

syn addition

Question 25

takes place when X and Y are added from opposite sides

Answer 25

anti addition

Question 26

Most alkene addition reactions are _____–the products are more stable (lower in energy) than the reactants.

Answer 26

exothermic

Question 27

Addition of HX (HCl, HBr, or HI) to an alkene gives a ____.

Answer 27

haloalkane

Question 28

process that favors bond formation at a particular atom over other possible atoms

Answer 28

regioselective

Question 29

states that, in hydrohalogenation of an unsymmetrical alkene, the hydrogen atom in the hydrogen halide forms a bond with the doubly bonded carbon atom in the alkene, bearing the greater number of hydrogen atoms.

Answer 29

Markovnikov’s rule

Question 30

Addition of water is called

Answer 30

hydration

Question 31

hydration is ____, usually by H2SO4

Answer 31

acid-catalyzed

Question 32

Virtually all alkenes add H2 in the presence of a transition metal catalyst, commonly ____

Answer 32

• platinum
  -palladium
• nickel

Question 33

Due to the presence of carbon-carbon multiple bonds, alkenes, and alkynes are very susceptible to ____.

Answer 33

oxidation

Question 34

If the potassium manganate(VII) solution is acidified with dilute sulfuric acid, the purple solution becomes _____.

Answer 34

colorless

Question 35

If the potassium manganate(VII) solution is made slightly alkaline (often by adding sodium carbonate solution), the purple solution first becomes dark green and then produces a _____ precipitate.

Answer 35

dark brown

Question 36

KMnO4 is a

Answer 36

Baeyer’s reagent

Question 37

• used to detect the presence of unsaturation in a molecule.
• the decolorization of the purple color of KMnO4 and the formation of a brown precipitate.

Answer 37

Baeyer’s Test: Hydroxylation

Question 38

The formation of glycol may be a prelude to the eventual cleavage of the double bond. When this happens, oxidation is classified as the _____.

Answer 38

oxidative cleavage

Question 39

Alkene oxidative cleavage occurs when the alkene is reacted with

Answer 39

• hot KMnO4
• O3 followed by H2O and Zn (ozonolysis)

Question 40

The products formed from oxidative cleavage

Answer 40

aldehydes, ketones, carbon dioxide, or acids

Question 41

A terminal doubly-bonded carbon atom that contains two hydrogen atoms is cleaved by hot KMnO4 to form CO2 and by ozonolysis to form _____.

Answer 41

formaldehyde

Question 42

substances having a general formula of CnH2n, also known as unsaturated HC.
It is composed of a double bond structure which has an angle of 120 degrees. One bond is sigma and the other one is called pi bond.

Answer 42

alkenes

Question 43

alkenes exhibit isomerism where the functional group and its position are the same but the carbon skeleton is different.

Answer 43

skeletal isomerism

Question 44

differs in the position of the functional group.

Answer 44

positional isomerism

Question 45

its double-bond alkene can have cis and trans isomerism.

Answer 45

geometrical isomerism

Question 46

The addition of hydrogen to alkenes may lead to the production of _____

Answer 46

alkanes