Alkenes and alcohols

Question 1

Explain the difference between primary, secondary and tertiary alcohols

Answer 1

Number of carbons bonded to the carbon attached to OH: primary =1, secondary =2, tertiary =3

Question 2

How are addition polymers named?

Answer 2

Poly(name of original alkene)

Question 3

What is the name of the functional group which makes an alcohol?

Answer 3

Hydroxyl (OH)

Question 4

Define an electrophile

Answer 4

An electron pair acceptor

Question 5

What is needed to turn an alcohol into a haloalkane?

Answer 5

Halide salt and sulfuric acid (makes HX in situ)

Question 6

How does stability of carbocation relate to the major and minor product in electrophilic addition of HX?

Answer 6

Major product is formed from the more stable carbocation

Question 7

Reacting an alkene with bromine makes

Answer 7

A dibromoalkane

Question 8

When can you have cis/trans isomers as well as E/Z?

Answer 8

When one of the bonded substituents on each C is the same

Question 9

Name two useful ways of disposing of polymers

Answer 9

Combustion for energy production; organic feedstock to make new plastics or other products

Question 10

Why do alcohols have higher BPs than alkanes?

Answer 10

Hydrogen bonds form between molecules; require more energy to break than London dispersion forces in alkanes

Question 11

Aside from conditions (reflux or distil), what else is important in oxidising primary alcohols to make the right products?

Answer 11

Equivalents of oxidising agent: just 1 to make aldehyde; 2 to make carboxylic acid

Question 12

Propan-2-ol + NaCl + H2SO4 with reflux makes

Answer 12

2- bromopropane

Question 13

What can tertiary alcohols be oxidized to?

Answer 13

Nothing

Question 14

Describe the colour change when dichromate successfully oxidises an alcohol

Answer 14

Orange to green ( dichromate (VI) to chromium (III)

Question 15

What type of mechanism do alkenes tend to react in?

Answer 15

Electrophilic addition

Question 16

What are addition polymers formed from?

Answer 16

Alkenes and substituted alkenes

Question 17

How do the Cahn-Ingold-Prelog rules for identifying E/Z isomers assign priority?

Answer 17

High priority = higher atomic numbers

Question 18

What are the two requirement’s for E/Z isomerism?

Answer 18

C=C double bond, and two different groups bonded to each of the carbons

Question 19

Why are alcohols soluble in water

Answer 19

Molecules can form hydrogen bonds with water molecules

Question 20

Alkenes + HBr make

Answer 20

bromoalkane

Question 21

Which experimental method is used to convert primary alcohols to carboxylic acids?

Answer 21

Reflux

Question 22

What can primary alcohols be oxidised to?

Answer 22

Aldehydes or carboxylic acids

Question 23

Which experimental method is used to convert primary alcohols to aldehydes?

Answer 23

Distillation

Question 24

What is the shape and bond angle around the C atom in an alkene?

Answer 24

120 deg, trigonal planar

Question 25

Alcohols undergo what to form carbon dioxide and water?

Answer 25

Complete combustion

Question 26

Reacting ethene with hydrogen and Ni catalyst makes

Answer 26

ethane

Question 27

How is oxidation symbolized in an equation?

Answer 27

[O]

Question 28

What is an oxidation reaction in organic chemistry?

Answer 28

A reaction where oxygen is added or hydrogen is removed from a compound

Question 29

What conditions are necessary for dehydration of an alcohol?

Answer 29

Concentrated phosphoric/sulphuric acid catalyst, heat and reflux.

Question 30

In the electrophilic addition mechanism what type of fission does the pi bond undergo?

Answer 30

Heterolytic fission to form ions

Question 31

Describe a C=C double bond

Answer 31

One sigma bond and one Pi bond

Question 32

Can double bonds rotate?

Answer 32

No - because pi bond would break if p orbitals are not aligned

Question 33

What reagent is used for the oxidation of alcohols?

Answer 33

Acidified potassium dichromate

Question 34

How can HCl gas from burning PVC be removed from waste mixture?

Answer 34

Neutralise with a base - eg sodium carbonate

Question 35

Define stereoisomers

Answer 35

Compounds with the same structural formula but different arrangements in space

Question 36

What is the test and positive result for an alkene?

Answer 36

Decolourises bromine water

Question 37

Describe the polarity of an alcohol molecule

Answer 37

Delta negative on the oxygen and delta positive on the adjacent C and H

Question 38

Identify a hazard of burning PVC - poly(chloroethene)

Answer 38

Releases toxic HCl gas

Question 39

What is a dehydration of an alcohol reaction?

Answer 39

One where water is eliminated from an alcohol

Question 40

What is added to an alkene to make an alcohol?

Answer 40

Steam, with acid catalyst eg phosphoric acid

Question 41

What can secondary alcohols be oxidized to?

Answer 41

Ketones

Question 42

What is the product of a dehydration of an alcohol rection

Answer 42

An alkene

Question 43

Why are alkenes more reactive than alkanes?

Answer 43

The pi bond has a relatively low bond enthalpy compared single sigma bonds

Question 44

How does a pi bond form?

Answer 44

Sideways overlap of adjacent p orbitals above and below the bonding atoms

Question 45

Name two types of sustainable polymers being formulated by chemists

Answer 45

Biodegradable and photodegradable polymers

Question 46

Name the alcohol CH3CH2CH2CH2OH

Answer 46

butan-1-ol

Question 47

What is markownikoffs rule?

Answer 47

When HX reacts with an unsymmetrical alkene, the H bonds to the C of the alkene which has more H already bonded.

Question 48

What is the structure of the repeat unit of poly(propene)

Answer 48

-CH2CH(CH3)-

Question 49

Which monomer makes the polymer which has [CH2CHCl] as its repeat unit?

Answer 49

chloroethene