alkenes

Question 1

saturated?

Answer 1

no

Question 2

functional group

Answer 2

Cn H2n

Question 3

H arrangement

Answer 3

planar, 120 degrees

Question 4

pi bond

Answer 4

exposed

high electron density

vulnerable to electrophiles

Question 5

stereoisomerism

Answer 5

same structural formula, different spatial arrangement, E-Z

Question 6

electrophile

Answer 6

electron pair acceptors

positive ions or polar molecules

Question 7

bromine water

Answer 7

orange to colourless

bromine added across C=C

Br polarised by negative charge and accepts electron pair and bonds to C.

Leaves Br- and Carboncation

room temp

Question 8

most stable carbocation

Answer 8

tertiary

most likely to form

Question 9

Sulphuric acid stage 1

Answer 9

C=C electrons to H+

:OSO2OH- to C+

forms alkyl hydrogensulfate

Question 10

sulphuric acid stage 2

Answer 10

cold water, then heat

forms alcohol

hydrolysis

H2SO4 released; catalyst

Question 11

hydrogen bromide

Answer 11

forms halogenoalkane

H-Br is polar

H attracted to C=C

C=C electrons to H

H-Br bond electrons to Br

Br- to C+

Question 12

why are polymers unreactive

Answer 12

strong C-C and C-H

Question 13

when are addition polymers formed

Answer 13

pi electrons in substituted alkene monomers form C-C bonds between molecules

saturated, unreactive

Question 14

main reaction to make addition polymers

Answer 14

combustion

Question 15

are addition polymers biodegradable

Answer 15

no

Question 16

properties of polymers

Answer 16

non polar

vdw

longer- closer-stronger vdw

long straight chains are strong, short branched are weak and flexible

Question 17

uses of polymers

Answer 17

unreactive

strong non polar covalent bonds

plastics

Question 18

modifying polymers

Answer 18

add plasticiser to make more flexible

plasticiser molecules get between chains and push apart and decrease strength of intermolecular forces; easier to bend

Question 19

reaction conditions

Answer 19

high pressure and temp

lower pressure and temp for straight chain

Question 20

low density polyethene

Answer 20

branched and softens at lower temps

Question 21

poly(chloroethene)

Answer 21

PVC

plasticiser

long, closely packed polymer chains. hard and brittle at room temp

used for drain pipes and window frames

plasticised PVC is more flexible; for electrical cable insulation, flooring tiles and clothing.