3.3.4 Alkenes

Question 1

What is a polymer

Answer 1

are molecules made from a large number of monomers joined together

Question 2

What is a monomer

Answer 2

The smaller units from which larger molecules are made

Question 3

What is addition polymerisation

Answer 3

Reaction in which many monomers with c=c form long chain of polymers as the only product

Question 4

Why are addition polymers unreactive

Answer 4

Non - polar and relatively strong

Question 5

What are the forces in an Alkene

Answer 5

Van der Waals
Because the chains are non-polar

Question 6

Give uses of PVC and why

Answer 6

Plastic pipes window frames
Rigid and hard

Question 7

Why is PVC rigid/hard

Answer 7

Presence of dipole-dipole interactions
Due to difference in electronegativity between chlorine and carbon

Question 8

How does a plasticiser work

Answer 8

Causes chains to move apart
Weakening intermolecular forces of attraction
Chains become flexible

Question 9

Formula for alkenes

Answer 9

C2 H2n

Question 10

Are alkenes saturated or unsaturated

Answer 10

Unsaturated c=c

Question 11

Why are alkenes highly reactive

Answer 11

Double bond has a high electron density
Pie and sigma bonds
Makes easier to attack

Question 12

Are alkenes soluble or insoluble in water

Answer 12

Insoluble in water

Question 13

Which is which E Z isomers

Answer 13

Z isomers together
E isomers opposite

Question 14

Priority in E Z isomers is determined by

Answer 14

Greater atomic number
(And the order in which bonded)

Question 15

What forces hold together long polymer chains and why

Answer 15

Van Der Waals
Because chains are non-polar

Question 16

What are uses of PVC with plasticiser x2

Answer 16

Flooring
Insulation in electrical cables

Question 17

What types of bonds are found around a c=c and which is where

Answer 17

Sigmas bond between both carbons
Pi bond found around

Question 18

How is the pi bond caused

Answer 18

Overlap of p orbitals

Question 19

Alkenes are soluble/insoluble in water

Answer 19

Insoluble

Question 20

Alkenes are …. Reactive because …..

Answer 20

Highly
Pi bond has high electron density so easier to attack

Question 21

Bond enthalpy of pi and sigma bonds explained

Answer 21

Pi bond enthalpy less than sigma bond
So pi bond is easier to break so more likely to take part in reactions

Question 22

Stereoisomers definition

Answer 22

Molecules with the same molecule and structural formula but different arrangement of atoms in space

Question 23

In what situation would there be non E Z isomers
Think what would the molecule need to have coming off c=c

Answer 23

One side has the same groups on both strands
So on one side two hydrogen etc

Question 24

What does the stability of an Alkene depend on

Answer 24

The number of alkyl groups that are bonded to the c+ in carbonisation step

Question 25

Do addition reaction of alkenes

Answer 25

DO IT RN Flashcards and book

Question 26

When symmetrical alkenes undergo electrophilic addition how many different products can be formed

Answer 26

Only ONE can go either side but it would still be the same product rotated

Question 27

When unsymmetrical alkenes undergo electrophilic addition how many products are formed + which is more likely

Answer 27

Two The hydrogen from the halide is more likely to bind to the carbon which has more hydrogens

Question 28

What does the stability depend on

Answer 28

The number of alkyl groups attached

Question 29

Which is most to least stable tertiary secondary primary alkanes

Answer 29

Teritary Secondary Primary The more carbons attached the more stable

Question 30

If it is more stable it is more likely to form the major/minor product

Answer 30

Major

Question 31

Test for alkenes

Answer 31

Bromine water Alkene - Turns from orange to colourless (must say turns) Alkanes - no observable reaction

Question 32

How to know which mechanism occurs with hydroxide ion

Answer 32

Nucleophilic Substitution Primary Aqueous Warm Nucleophilic Elimination Concentrated Hot Elimination Ethanol solvent Tertiary

Question 33

What is an electrophile

Answer 33

Electron pair acceptor ( they are deficient in electrons )

Question 34

How is an alkyl hydrogen sulfate converted to an alcohol

Answer 34

Add cold water Will have alcohol + sulfuric acid Process called hydrolysis