C2

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  • Created by: Faith16
  • Created on: 30-03-16 15:40
What are chemicals made from?
Atoms or groups of atoms that have bonded together
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What is a mixture of chemicals?
Contains different substances that are not chemically bonded together e.g. rock salt mixture of salt and sand
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What materials are from plants?
Wood, paper (trees) and cotton (from cotton plants)
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What materials are from animals?
Wool (sheep), silk (made by silk worm larva) and leather (cows)
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What materials are synthetic (man made)?
Rubber (made in factories so can control properties), clothes e.g. nylon or polyester (can made water-prook, stretchy or sparkly) and paints
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What are different properties of materials?
Melting point, strength, stiffness, hardness, density.
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What is tensile strength and compressive strength?
Tensile- how much an object can resist a pulling force e.g. ropes and cables. Compressive- how much an object can resist a pushing force e.g. bricks
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What are different properties of plastics?
Can be fairly hard, strong and stiff, some have a fairly low density, some are mouldable e.g. cases for televisions, computers and kettles
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What are different properties of rubber?
Strong but soft and flexible, mouldable e.g. rubber car tyres
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What are the different properties of nylon fibres?
Soft and flexible, good tensile strength e.g. rope and clothing fabric
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What does the material a product is made from affect?
How durable it is and how effective it is.
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What is crude oil?
A mixture of hydrocarbons
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What happens as a hydrocarbon chain gets longer?
The properties change
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What are intermolecular forces and how do you break them?
Attraction between the hydrocarbons- as you heat them the particles are supplied with more energy so they move more overcoming the intermolecular forces and becoming gas.
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What are covalent bonds?
Bonds between the hydrogen and carbon in each hydrocarbon molecule- they do not break (stronger than intermolecular forces)
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What method is used to separate crude oil?
Fractional Distillation
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How does fractional distillation work?
The hydrocarbons are separated into groups with different boiling points as they have the same chains
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What can crude oil be used for?
Bitumen (road surfaces), lubricating oil, diesel, kerosene (jet fuel), naphtha (base for many chemicals), petrol and refinery gas
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What can a small amount of hydrocarbons be used for?
New compounds for use in things such as plastics, medicines, fertilisers and food
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How are plastics formed?
When lots of small molecules called monomers join together to make a long molecule called a polymer
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What are different physical properties of polymers?
Strong and rigid (for plastic milk bottles), light and stretchable e.g. low-density polymers (used for plastic bags and squeezy bottles), heat-resistance (kettles) and polystyrene foam (used in packing)
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What can PVC be used for?
Can be strong and durable or rigid (window framings and piping) or stretchy (synthetic leather)
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What are the advantages and disadvantages of using synthetic fibres such as nylon and polyester?
Advantages- Lighter,more durable, water-resistant and often cheaper. Disadvantage- not breathable to may make them uncomfortable next to the skin
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Why has PVC replaced wood for window frames?
As PVC is weather- resistant, strong and durable so it makes windows more secure also the frames do not need painting every few years .
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How does a polymer change depending on how close together or far way the chains are?
The closer together the chains the higher density, further away low density
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What are the properties of a polymer with weak forces?
The chains are able to slide over each other meaning the plastic can be stretched easily and it will have a low melting point
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What are the properties of a polymer with strong forces?
The plastic will have a higher melting and boiling point and can't be stretched easily
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How can polymers be made stronger?
By adding cross-linking agents
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What can be used to reduce the forces between polymer chains?
Plasticisers
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What is a crystalline polymer?
A polymer that has straight chains with no branches so the chains can fit close together- have a high density, strong and have high melting and boiling points
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What is nanotechnology?
Technology that is made using nanoparticles
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What types of nanoparticles occur naturally?
Seaspray producing nanoscale salt particles and combustion causing soot particles to form
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How is nanotechnology used?
Added to plastics in sports equipment (makes them stronger, more durable and don't add weight) and silver nanoparticles are added to polymer fibres for surgical masks and wound dressing (antibacterial properties)
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What are the affects of nanoparticles on the body?
It has not yet been discovered but people believe products should be labeled so people have a choice
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Other cards in this set

Card 2

Front

What is a mixture of chemicals?

Back

Contains different substances that are not chemically bonded together e.g. rock salt mixture of salt and sand

Card 3

Front

What materials are from plants?

Back

Preview of the front of card 3

Card 4

Front

What materials are from animals?

Back

Preview of the front of card 4

Card 5

Front

What materials are synthetic (man made)?

Back

Preview of the front of card 5
View more cards

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