Hydrocarbons and Polymers

Question 1

What is the general formula for the alkanes?

Answer 1

CnH2n+2 (n = number of carbon atoms)

Question 2

How many bonds do carbon atoms need to have in alkanes and alkenes?

Answer 2

4

Question 3

Are alkanes saturated?

Answer 3

Yes, they only have C-C bonds, not C=C bonds

Question 4

What is the general formula of alkenes?

Answer 4

CnH2n

Question 5

What is the general word equation for a reaction between an alkene and oxygen?

Answer 5

Alkene + oxygen → carbon dioxide + water

Question 6

Write the word equation for a reaction between ethene and bromine

Answer 6

Ethene + bromine → diobromoethane (C2H4Br2)

Question 7

Are alkenes saturated?

Answer 7

No, they’re unsaturated as they have C=C bonds

Question 8

What is the test for alkenes?

Answer 8

Add a few drops of bromine water to the substance that you’re testing, if it stays orange it’s an alkane, if it’s decolourised then it’s an alkene

Question 9

What are addition polymers?

Answer 9

Relatively large molecules made by combining smaller molecules containing C=C bonds. Polymers have high relative atomic mass, they’re made up of small repeating units

Question 10

What are the properties and uses of poly(ethene)?

Answer 10

Flexible, cheap, good electrical insulator. Used for plastic bags, plastic bottles and clingfilm

Question 11

What are the properties and uses of poly(propene)?

Answer 11

Flexible, shatterproof, has a high softening point(similar to melting point). Used in buckets and bowls

Question 12

What are the properties and uses of poly(chloroethene) (PVC)?

Answer 12

Tough, cheap, long lasting, good electrical insulator. Used in window frames, gutters and pipes, insulation for electrical wires

Question 13

What are the properties and uses of poly(tetrafluoroethene)?

Answer 13

Tough, slippery, resistant to corrosion, good electrical insulator. Used in non-stick coatings for frying pans, containers for corrosive substances and insulation for electrical wires

Question 14

What are polyesters?

Answer 14

Condensation polymers

Question 15

Which 2 different monomers do polyesters need?

Answer 15

A molecule containing two carboxylic acid groups and a molecule containing two alcohol groups

Question 16

When is an ester link formed?

Answer 16

Each time two different monomers react together

Question 17

How many products are formed in condensation polymerisation?

Answer 17

2, water molecules and a polymer

Question 18

What structure does DNA have?

Answer 18

Double helix, there are 4 bases, A pairs with T, G pairs with C

Question 19

What are the monomers for DNA?

Answer 19

Nucleotides

Question 20

What are the monomers for proteins?

Answer 20

Amino acids

Question 21

What is the monomer for starch?

Answer 21

Glucose

Question 22

What is the main raw material needed to make addition polymers and most condensation polymers?

Answer 22

Crude oil

Question 23

How can polymers be disposed of?

Answer 23

• Landfill, this is negative because polymers are not biodegradable so they last for many years, we are also running out of landfill sites
• Burning, this is negative because polymers release toxic gases when they burn
• Recycling, positive
• Biodegradable polymers are being developed, positive

Question 24

What are the positives of landfill sites?

Answer 24

• Waste is disposed of quickly

- Waste is out of sight once it’s covered over

Question 25

What is the main advantage of polymers being non-biodegradable?

Answer 25

Objects made from polymers last for a long time

Question 26

What are the main disadvantages of landfill sites?

Answer 26

- Landfill spaces are running out - Most polymers are non-biodegradable so they last for many years - They're unsightly and attract pests