Alkanes

Question 0

What is the general formulae for an Alkanes ?

Answer 0

CnH2n+2

Question 1

What words (sentence) do we use to remember the names of the Alkanes in order?

Answer 1

My (Methane), elephant (Ethane), prefers (propane), bananas (Butane), peeled (pentane).

Question 2

Alkanes are an …….series?

Answer 2

Homologous series of saturated hydrocarbons.

Question 3

Homologous series is a series if compounds which; (4)

Answer 3

• have the same general formula
• have the same chemical properties
• have the same physical properties which increase up the series
• differ from their nearest neighbour in molecular formula by a constant amount, CH2

Question 4

What is a hydrocarbon?

Answer 4

A compound made up of carbon and Hydrogen only.

Question 5

What is the definition of Saturated?

Answer 5

Only contains single bonds

Question 6

What does the boiling point do as the carbon chain increases?

Answer 6

Increases

Question 7

All Alkanes burn in excess oxygen to form…..? (2 substances)

Answer 7

Carbon dioxide and Water

Question 8

What is a STRUCTURAL ISOMERISM?

Answer 8

2 or more compounds which have

• the same molecular formula
• different structural formula

Question 9

Combustion

Answer 9

When Alkanes burn in excess of oxygen they give out large amounts of HEAT ENERGY hence they make good fuels.

Question 10

What are the products of the combustion of Alkanes?

Answer 10

Carbon dioxide

Water

Question 11

What is the equation for the combustion of Alkanes?

Answer 11

……………+Oxygen=Carbon Dioxide+Water

Question 12

What are the observations when Alkanes react with halogens?

Answer 12

• 2 layers form

- orange layer SLOWLY goes colourless

Question 13

What is the equation for complete combustion?

Answer 13

Alkanes (Hydrocarbon)+excess oxygen= carbon dioxide + water

Question 14

If there is a LIMITED SUPPLY OF EXYGEN what is the equation for the complete combustion?

Answer 14

Alkanes+limited supply if oxygen = carbon monoxide +water

Question 15

What three words go with CARBON MONOXIDE that all end in ‘s’…!!!!!!

Answer 15

Colourless
Odourless
Poisonous

Question 16

In which 3 scenarios does INCOMPLETE COMBUSTION take place?

Answer 16

• car engines
• boiler in a poorly ventilated situation
• Calourgas heater in a poorly ventilated room

Question 17

What is the equation for cracking?!!!!

Answer 17

Heat

Long chain alkane >short chain+alkene. Catalyst

Question 18

What are Alkanes used for

Answer 18

Making plastic

Question 19

What are short chain Alkanes used for?

Answer 19

Used as fuels

Question 20

What fractions are usually cracked?

Answer 20

Long chain or medium chain hydrocarbons

Question 21

What are polymers?

Answer 21

Long chain molecules which are mad when small molecules Called Momomers are added together.

Question 22

Unsaturated Alkanes with carbon-carbon double bonds can act as….??

Answer 22

Monomers

Question 23

When monomers are heated up with an “initiator” and put under high pressure what happens to form a polymer?

Answer 23

The double bonds open up to form a very long chain of single bonded carbon atoms. ADDITION POLYMERISATION

Question 24

What is the repeating pattern if atoms along the polymer chain called?

Answer 24

Repeating unit

Question 25

What do the properties of the polymer depend upon? (3)

Answer 25

- The monomer it's made from - The conditions it's made under - Whether or not it has cross links

Question 26

Whey comes as a result of polymer chains not all being the same length?

Answer 26

It's physical properties are more of mixture.

Question 27

How many isomers does propene have?

Answer 27

NONE!!!!!!

Question 28

What are the properties of polyethene/ethene? (4)

Answer 28

- low density form LDPE - Very flexible light but not very strong - high density form HDPE - Light and strong/more ridged

Question 29

Uses of Ethene/polyethene? (2)

Answer 29

- plastic shopping bags | - drink Bottles, Buckets and Bowls

Question 30

What are the properties of propene/polypropene? (1)

Answer 30

Very tough and strong

Question 31

What uses does propene/polypropene have? (3)

Answer 31

Crates Ropes Carpets

Question 32

What are the properties of chloroethene (vinyl chloride)/polychloroethene (PVC)? (2)

Answer 32

- Ridged and very waterproof | - very resistant to chemicals

Question 33

What are the uses of chloroethene (vinyl chloride)/polychloroethene (PVC)? (2)

Answer 33

- wellies - credit cards - gutters bad drain pipes - window frames - insulating coating for electrical wires

Question 34

What are the properties of phenylethene (styrene)/polystyrene (PS)? (1)

Answer 34

Hard and brittle but can be expanded with gas

Question 35

What are the uses of phenylethene (styrene)/polystyrene (PS)? (4)

Answer 35

- Foam packaging - cups - fast food cartons - electrical insulation

Question 36

What's a monomer?

Answer 36

Small molecule with a double bond | e.g. C=C

Question 37

What does UNSATURATED mean?

Answer 37

A compound contains a DOUBKE BOND.

Question 38

What's the general formulae for Alkenes?

Answer 38

CnH2n