Organic Chemistry Pt 2

Question 1

Polymerisation definition

Answer 1

The process of producing long chain molecules from small molecules

Question 2

Addition polymerisation definition

Answer 2

How monomers can join together to form very long chain molecules called polymers

Question 3

Properties of polythene

Answer 3

Light, flexible and resistant to attack by acids and alkalis

Question 4

Uses of polythene

Answer 4

Cling film, plastic bags, bottles

Question 5

Properties of PVC

Answer 5

tough, durable, waterproof and good insulator

Question 6

Uses of PVC

Answer 6

Electric cables, guttering, drain pipes

Question 7

Name four benefits of plastics

Answer 7

Less dense than other materials
Resistant to chemicals and water
Excellent insulation properties
Extremely long lasting

Question 8

Name the monomer that is used to make polythene

Answer 8

Ethene

Question 9

What type of reaction is used to make polythene

Answer 9

Addition polymerisation

Question 10

Give the molecular formula and structural formula of propene

Answer 10

C3H6

Question 11

Write a symbol equation to show how PVC is made from vinyl chloride

Answer 11

See sheet

Question 12

Advantages of landfill

Answer 12

Local treatment so less transport is needed

Landscape can be re-landscaped after use

Question 13

Disadvantages of landfill (2)

Answer 13

Wastes land

Polluting gases released

Question 14

Advantages of incineration (2)

Answer 14

• less waste going to landfill

- heat energy can generate electricity

Question 15

Disadvantages of incineration

Answer 15

• ash residue is toxic

- polluting gases are released

Question 16

What are biodegradable plastics made from

Answer 16

Maize starch

Question 17

Explain the term non-biodegradable

Answer 17

Materials that cannot be broken down by microbes

Question 18

Give three ways that councils are promoting the recycling of plastics

Answer 18

• imposed on household to pay for dumping plastics
• councils run information sessions
• Council provides collection points in supermarkets and provide on support kerb side recycling

Question 19

Complete Combustion of alcohols

Answer 19

• Burn with a clear blue flame

- Heat is released

Question 20

Homologous series of alcohols general formula :

Answer 20

CnH2n+1OH

Question 21

Describe ethanol

Answer 21

• A water soluble miscible liquid

Question 22

Molecular and structural formula of methanol

Answer 22

CH3OH
H
H- C - O - H
H

Question 23

Molecular formula of ethanol

Answer 23

C2H5OH
H H
H - C - C - O - H
H H

Question 24

Propan-1-ol molecular formula

Answer 24

C3H7OH
H. H. H.
H - C - C - C - O - H
H. H. H

Question 25

Propan-2-ol molecular formula

Answer 25

C3H7OH H. OH H H - C - C - C - H H. H. H

Question 26

State of alcohols as room temperature

Answer 26

Liquid

Question 27

Describe the preparation of ethanol from sugars by fermentation (4)

Answer 27

- Yeast is added to water and sugar in the absence of air - It is left in a warm, dry place (36 degrees) for a few days - Fermentation occurs giving ethanol and bubbles of carbon dioxide - Reaction is brought about by the enzyme zymase which is present in yeast

Question 28

What does ethene and steam produce ?

Answer 28

Ethanol

Question 29

Describe the oxidation of alcohols when exposed to air

Answer 29

By leaving ethanol in air over time it will be oxidised to ethanol acid by oxygen

Question 30

Describe the reaction of ethanol with acidified potassium dichromate solution (4)

Answer 30

- Potassium dichromate (K2Cr2O7) is a common oxidising agent - Reacting it with alcohols is carried out in a test tube with the alcohol mixed with acidified potassium dichromate solution - The test tube is then placed in a beaker of warm water - A colour change from orange to green is observed

Question 31

Structural formula of oxidised Methanol

Answer 31

``` Methanoic acid O // H - C \ OH ```

Question 32

Structural formula of oxidised ethanol

Answer 32

Ethanoic acid ``` H O | // H - C - C | \ H. OH ```

Question 33

Structural formula of oxidised propan-1-ol

Answer 33

Propanoic acid ``` H. H O | | // H - C - C - C | | \ H. H OH ```

Question 34

recall the molecular formula of carboxylic acids and what they form

Answer 34

``` - Methanoic acid HCOOH forms methanoate salts - HCOO- - Ethanoic acid CH3COOH forms ethanoate salts - CH3COO- - Propanoic acid CH3CH2COOH forms propanoate salts - C2H5COO- - Butanoic acid CH3CH2CH2COOH forms butanoate salts - C3H7COO- ```

Question 35

State at room temperature and pressure of the carboxylic acids

Answer 35

Liquid

Question 36

Are carboxylic acids weak?

Answer 36

carboxylic acids are weak acids as they are only partially ionised in solution

Question 37

Reaction of ethanoic acid with sodium carbonate

Answer 37

Observations - Bubbles of gas are formed, white solid disappears and a colourless solution forms 2CH3COOH + NA2CO3 —> 2CH3COONa + H2O + CO2 Only carboxylic acids will release carbon dioxide when sodium carbonate is added to a sample

Question 38

Reaction of propanoic acid with magnesium

Answer 38

Observations - Bubbles of gas produced, heat released, grey solid disappears and a colourless solution forms 2C2H5COOH + Mg —> (C2H5COO)2Mg + H2

Question 39

Reaction of butanoic acid with sodium hydroxide

Answer 39

Observations - Heat is released and solution remains colourless CH3CH2CH2COOH + NaOH —> C3H7COONa + H2O

Question 40

How is combustion of fuels a major source of atmospheric pollution (3)

Answer 40

• combustion of hydrocarbons producing carbon dioxide, which leads to the greenhouse effect causing sea level rises, flooding and climate change; • incomplete combustion producing carbon monoxide (toxic) and soot (carbon particles), which cause lung damage • presence of sulfur impurities in fuels, which leads to acid rain damaging buildings, destroying vegetation and killing fish

Question 41

Reactions of Alkanes, alkenes, alcohols and carboxylic acids when warmed with acidified potassium dichromate solution

Answer 41

Alkane - Solution remains orange Alkene- Solution remains orange Alcohol - Solution changes from orange to green Carboxylic acid - solution remains orange

Question 42

How is the atmospheric pollutant Sulfur dioxide produced and problems it causes (3)

Answer 42

- Many fuels contain Sulfur impurities which burn and produce acidic Sulfur dioxide - Sulfur dioxide reacts with water in the atmosphere to form sulfurous acid which falls as acid rain - acid rain can damage buildings and vegetation

Question 43

How is soot formed and what problems it causes

Answer 43

- Incomplete combustion of fuels | - Carbon particles pollute the air and cause lung damage

Question 44

What happens as propan-1-ol undergoes oxidation

Answer 44

Forms propanoic acid

Question 45

Distinguishing different organic families using bromine water solid sodium carbonate potassium dichromate

Answer 45

Alkane - N N N Alkene - Y N N Carboxylic acid - N Y N Alcohol - N N Y

Question 46

How is carboxylic acid weak?

Answer 46

They have the typical reactions of an acid with metals, bases and carbonates. However they will react more slowly

Question 47

Main advantage of recycling addition polymers? (1)

Answer 47

- Thermoplastics can be remoulded

Question 48

What process is used to obtain a concentrated solution of ethanol from the fermentation solution

Answer 48

Ethanol can be separated from yeast by fractional distillation

Question 49

Combustion of methanol | Complete and incomplete

Answer 49

2CH3OH + 3O2 —> 2CO2 + 4H2O CH3OH + O2 —> CO + 2H2O