Hertswood Academy Gcse Chemistry C1 5 Other Useful Products From Crude Oil

Front 1

1. What is cracking?

Back 1

• Breaking down large hydrocarbon molecules into smaller hydrocarbons.

Front 2

2. Why is cracking important?

Back 2

• Large hydrocarbon molecules are not useful as fuels as they have high boiling points do not burn easily and are difficult to vaporise. Cracking long chained molecules into short chained molecules makes them more useful.

Front 3

3. What type of reaction does cracking involve?

Back 3

• Thermal decomposition

The long chained hydrocarbons are being broken down into short chained hydrocarbons in a high temperature.

Front 4

4. What are the products of cracking?

Back 4

• Alkanes and alkenes.

Front 5

5. How is cracking carried out?

Back 5

• Alkane is heated then vaporised and passed over a hot catalyst or mixed with steam.

Front 6

6. What are alkenes?

Back 6

• Alkenes are unsaturated hydrocarbons that contain a carbon to carbon double bond (C=C).

Front 7

7. What is the general formula for alkenes?

Back 7

• CnH2n

Front 8

8. What is the test for an alkene?

Back 8

• Alkenes will react with bromine water decolourising it turning it from orange to colourless.

Front 9

9. What is a monomer?

Back 9

• Small alkene molecules

Front 10

10. What is a polymer?

Back 10

• Very large molecules made up of monomers.

Front 11

11. What is the repeating unit for a polymer made up of ethene monomers (poly(ethene))?

Back 11

Front 12

12. Poly (ethene) is a useful plastic. Give 3 uses of poly(ethene).

Back 12

• Plastic bag

• Cling film

• Plastic drinks bottles or dust bins.

Front 13

13. Give 2 uses of poly(propene).

Back 13

• Carpets

•Ropes

• Milk crates.

Front 14

14. Give 3 new uses of polymers that are currently being developed?

Back 14

• Light sensitive plasters- stickiness can be switched off before the plaster is removed

•Hydrogels- contain cross links to trap water. Used for wound dressings and contact lenses

• Shape memory polymers- used for stitches that will keep the sides of a cut together. Change in temperature causes the polymer to change shape. When a wound is healed the polymer is designed so the stitches will dissolve

• New polymer material for dental fillings: mercury is toxic and dentists who work with it every day are at risk therefore new polymer material is being developed.

Front 15

15. What is the problem with disposing plastic in landfill sites?

Back 15

• Plastics are non-biodegradable which means they do not decompose.

Front 16

16. What problems can non-biodegradable plastics lead to?

Back 16

• Wildlife can get trapped in the waste or eat the plastic and could die

• Plastics take up valuable space in landfill sites as they take years and years to break down completely

• Increased litter on the streets

Front 17

17. What is a biodegradable plastic?

Back 17

• A biodegradable plastic is one that is made from plant materials and can be broken down by microorganisms.

Front 18

18. What are the 2 ways that ethanol can be produced?

Back 18

• Fermentation

(C6H12O6 → 2C2H5OH +

• HydrationCO2)

(C2H 4 + H 2 0 → C 2 H 5 OH)

Front 19

19. How is ethanol made by fermentation?

Back 19

• To make alcoholic drinks sugar from plants is fermented. Enzymes in yeast breakdown the sugar into ethanol and carbon dioxide.

• C6H12O6 → 2C2H5OH + CO2

Front 20

20. How is ethanol made by hydration?

Back 20

• Ethanol for industrial use is made from ethene gas. Ethene is made when crude oil is cracked. Ethene reacts with steam in the presence of a catalyst to make ethanol.

Front 21

21. What is a catalyst?

Back 21

• A catalyst is a substance that increases the rate of a reaction without being used up in the reaction.

Front 22

22. What are the advantages and disadvantages of making ethanol by fermentation?

Back 22

• Advantages:-

-Sugar plants are a renewable resource

-Carbon neutral (it only releases the same amount of carbon it absorbed)

• Disadvantages:-

-Fermentation is a batch process which takes a lot longer.

-Ethanol produced is not pure and has to be refined

-Land used to grow crop can’t be used to grow food

Front 23

23. What are the advantages and disadvantages of making ethanol by hydration?

Back 23

• Advantages:

Hydration is a continuous process so produces ethanol much faster.

Ethanol produced is pure.

• Disadvantages:

Hydration relies on using ethene from crude oil which is a non-renewable resource.

High temperatures require lots of energy so high costs and emission of CO2 (greenhouse gas/global warming).