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Flashcards in Organic Chemistry Deck (39):
1

Saturated definition

Only single bonds in a molecule

2

Unsaturated definition

A molecule containing a double bond

3

Isomerism

- A group of compounds which share:
• same functional group
• same general formula
• same chemical reactions
• gradual change in physical properties

4

Hydrocarbon definition

A compound containing only carbon and hydrogen

5

Alkanes formula

Cn H2n+2

6

Uses of alkanes

Fuels

7

Order of alkanes

Methane, ethane, propane, butane, pentane

8

Complete combustion of alkanes

- A blue flame indicates complete combustion:

Methane + oxygen -> carbon dioxide + water

CH4 (g) + 2O2 -> CO2 + 2H2O

9

Incomplete combustion of alkanes

- when oxygen supply is limited, a yellow flame is produced so incomplete combustion occurs:

Methane + oxygen -> carbon + water

CH4 + O2 -> C + 2H2O

10

What else can be produced in incomplete combustion of Alkanes? (Fuels)

Carbon monoxide

Methane + oxygen-> carbon monoxide + water

2CH4 + 3O2 -> 2CO + 4H2O

Carbon monoxide is poisonous because it reduces the capacity of the blood to carry oxygen

11

A substitution reaction with alkanes

- methane with bromine, in the presence of UV light, a substitution reaction occurs:

Methane + bromine -> bromomethane + hydrogen bromide

CH4 + Br2 (g) -> CH3Br (g) + HBr

12

Alkenes formula

Cn H2n

13

Uses of alkenes

Making polymers

14

Order of alkenes

Ethene, propene, butene, pentene.

15

Additional reaction with alkenes

- alkenes react with bromine so the bromine water loses its colour

Ethene + bromine -> dibromoethane
(Colourless Gas)(orange Liquid)(colourless liquid)

16

What is in crude oil

Refinery gases - camping gas
Gasoline - petrol
Kerosene - fuel for planes
Diesel - fuel for vans/lorries (diesel)
Fuel oil - fuel for ships/heating systems
Bitumen - tar on roads

17

How do the length of the molecules change in the fractional column and temperature

As you go up the column, the molecules get smaller
Increased length- increases boiling point

18

How does the viscosity change in the column

As the chain length increases, viscosity increases

19

Volatility definition

Volatility is the tendency of a substance to vapourise

20

What are the conditions for cracking

600-700° C
Silica or alumina catalyst

21

What could you use to test for alkenes

Bromine water (turns from brown -> colourless)

22

General characteristics of any homologous series

- different physical properties
- presented by the same general formula
- same chemical characteristics

23

Manufacture of ethanol

- passing ethene and steam over a phosphoric acid catalyst
- temperature of 300° C
- pressure of 60-70 atm

24

Fermentation

- sugar is converted to ethanol using yeast (enzyme is zymase)
- requires 30° C

25

Dehydrating ethanol

C2H5OH —> C2H4 + H2O

- ceramic wool soaked in ethanol
- aluminium oxide catalyst

26

Making ethanol from Ethene, advantages and disadvantages

Advantages
- fast continuous process
- Large amounts of ethanol produced

Disadvantages
- uses nonrenewable resources
- flavours have to be added artificially

27

Making ethanol from Fermentation, advantages and disadvantages

Advantages
- uses renewable resources
- produces flavour of alcoholic drinks

Disadvantages
- slow ‘batch’ process
- only small amounts of ethanol produced
- what produced isn’t pure

28

Polymerisation

- The joining up of lots of little molecules, called monomers, to form a big molecule called a polymer

29

2 types of polymerisation

Additional polymerisation
Condensation polymerisation

30

Addition polymerisation

When alkenes add together to form the polymer

E.g. styrene —> polystyrene

31

Condensation polymerisation

- requires two different monomers
- The monomers react together and bonds form
- with each new bond formed, small molecule is lost e.g. a water molecule (condensation)

E.g nylon

32

Uses of polymers

Polyethene- light, waterproof, for plastic bags
Polypropene- heat resistant, kettles
Polychloroethene- water pipes, insulation on electrical cables

33

What is a monomer

A molecule that can combine with others to form a polymer

34

What is a polymer

A large molecule made up of linked monomers

35

Draw the repeat unit of addition polymers

- poly(ethene)
- poly(propene)
- poly(chloroethene)

36

Why are addition polymers hard to dispose of

Because of their inertness means they do not easily biodegrade

37

What is a homologous series

A group of organic compounds with the same general formula, similar chemical properties and physical properties that change gradually from one member of the series to the next

38

What is a general formula

It is a type of empirical formula that represents the composition of any member of an entire class of compounds.

39

What do cars produce which contribute to acid rain

Nitrogen oxide