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Chemistry Revision > C2 > Flashcards

C2 Flashcards

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1
Q

What kind of materials come from plants?

A

Wood and paper are both made from trees , cotton comes from the cotton plant

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2
Q

Materials come from animals?

A

Wool comes from sheep. Silk is made by the silkworm larva. Leather comes from cows.

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3
Q

What materials are made by man?

A

Rubber, nylon, polyester, paint mixtures

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4
Q

Name an advantage of making rubber in a factory

A

Control its properties, making it suitable for different purposes e.g. wetsuits

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5
Q

Where are the role materials used to make synthetic materials found?

A

They come from the Earth crossed. E.g. aluminium and Crimean are used in a lot of metal alloys

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6
Q

What are material is made up of?

A

Absolutely every material is made up of chemicals Either individual chemicals or mixture of chemicals

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7
Q

What is strength?

A

Strength is how good a material is that resisting a force, can judge how strong is by how much force is needed to Eva break it or permanently change shape

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8
Q

What are the two types of strengths

A

Tensile or tension strength and compressive strength

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9
Q

What is tensile strength?

A

It is how much I miss you can resist a putting forth. Things like ropes and cables need a high tensile strength or they’d snap.

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10
Q

What is compressive strength?

A

This is how much I material can resist a pushing force. Building materials like bricks need good compressive strength or they’d be squished by the Weight of bricks above them.

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11
Q

What is stiffness and give an example of material that is stiff?

A

Stiffness is how good something is not bending when a force is applied to it E.g. steel as they are very difficult to bend so they are stiff.

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12
Q

What is hardness and give an example of something that is hard?

A

Hardness of materials is how difficult it is to cut into E.g. diamond as the only material that can cut a diamond is another diamond

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13
Q

What is density and give an example of something that is dense and isn’t dense?

A

Density is a materials mass per unit volume. There is not very dense you’d need a huge volume of it to make up one KG in mass. But gold is very dense a small volume of gold would make up one KG in mass.

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14
Q

Give some of the properties of plastic?

A

Can be fairly hard, strong and stiff. Some are fairly low density. Some are mouldable.

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15
Q

Give some of the properties of rubber?

A

Strong but soft and flexible, mouldable e.g. Rubber car tyres

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16
Q

What are the properties of nylon fibres?

A

Soft and flexible. Good tensile strength e.g. ropes and clothing fabric

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17
Q

A products properties depend on the materials it’s made from. Give an example of this

A

Gramophone records 100 years ago when made of mixtures of materials like paper, slight and wax. There aren’t many of these records E cause they broke very easily more modern records are made of polyvinyl chloride PVC or vinyl this material is strong and flexible so it’s less likely to break.

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18
Q

What properties do materials used for cooking products need to have?

A

I need a high melting point that’s not toxic.

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19
Q

Suitability for a toy car?

A

Italy, Spain non-toxic and should be strong, stiff and low-density e.g. some kind of plastic.

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20
Q

what is a molecule?

A

A molecule is a group of atoms bonded together.

21
Q

What is crude oil?

A

Crude oil is a mixture of hydrocarbons

22
Q

What are hydrocarbons?

A

Hydrocarbons are molecules that are made of chains of carbon and hydrogen atoms only. These chains are of varying lengths.

23
Q

Why do hydrocarbons properties change as the chain gets longer?

A

As the length of the carbon chain changes, The properties of the hydrocarbon change. Short chain molecules have low boiling points – they’re often gases. Long chain molecules have high boiling point and can be quite vicious(thick and sticky)

24
Q

What are the two important types of bond in crude oil.

A

strong covalent bonds between the carbons and hydrogen is within each hydrocarbon molecule. and intermolecular forces of attraction between different hydrocarbon molecules in the mixture.

25
Q

What happens when crude all mixture is heated?

A

The molecules are supplied with extra energy this make someone a good move about more eventually and Monica might have enough energy to overcome The intermolecular forces that keep it with that of molecules and can go whizzing off as a gas.

26
Q

Why are big molecules harder to break up than smaller ones

A

because the intermolecular forces of attraction on much stronger between big molecules then they are between small molecules this is why big molecules have higher boiling points than smaller molecules do.

27
Q

What is fractional distillation

A

This is where hydrocarbons are separated into groups of different boiling points. Each group is called a fraction, and the hydrocarbons within a fraction have similar boiling points.

28
Q

Why is each fraction made up of Hydrocarbons with similar chain lengths.

A

Your carbon chains have similar boiling points if they are similar lengths.

29
Q

How are plastics formed?

A

When lots of small molecules called monomers joined together to make A very long molecule called a polymer and are usually carbon based

30
Q

What happens when small molecules are under high pressure?

A

They polymerise (join hands) to form long chains called polymers

31
Q

What are the different types of polymers?

A

Strong, rigid polymers – light, stretchable polymers – heat resistant polymers

32
Q

Give an example of a strong, rigid polymer?

A

such as high density polythene are used to make plastic milk bottles

33
Q

Give an example of a light, stretchable polymer?

A

Such as low density polythene are useful plastic bags and squeezy bottles low-density polythene has a low melting point.

34
Q

give an example of a heat resistant polymer?

A

such as Melamine resin and polypropene are used to make plastic kettles

35
Q

Polymers are used as alternatives to traditional materials in loads of applications give examples of this?

A

Synthetic fibres like nylon and polyester or after neutral place cotton, or silk fabrics compared with natural alternative these synthetic fibres tend to be lighter, more durable, water resistant and often cheaper the main disadvantage of my many synthetic fabrics is that they aren’t breathable which can make them uncomfortable next to skin and rigid PVC have a largely replaced would as material for new window frames as it weather resistant, strong and durable, which makes one is more secure and means the frames do not need painting every few years

36
Q

How do the properties of a polymer affected by the way it’s made?

A

The Polymers property also depends on the way the chain is arranged so if the polymer chains are packed close together, the material will have a high density. And if the polymer chains are spread out, The material will have a low density.

37
Q

The forces between the different chains of the polymer hold it together as a solid mass what happens if a polymer has a weak force?

A

The chains held together by weak forces are free to slide over each other this means four example plastic can be stretched easily and will have a low melting point.

38
Q

It happens if a polymer have a strong force?

A

Plastics with stronger bonds between the polymer chains have high melting points and can’t be easily stretched as the cross links hold The chain firmly together. Cross links are chemical bonds between the polymer chains

39
Q

What is the difference between a polymer with short chains and a polymer with long chains?

A

Polymers with short chains are easy to shape and have a lower melting points along the chain polymers are stiffer and have high melting points

40
Q

How can polymers be made stronger?

A

They can be made stronger by adding cross links. These agents chemically bonded chains together making a polymer is stiffer, stronger and more heat resistant.

41
Q

How can polymers be made weaker?

A

Plasticisers can be added to a polymer to make it soft and easy to shape. Plasticisers work by getting in between the polymer chains and reducing the forces between them.

42
Q

What are the benefits of crystalline polymers?

A

They have higher density are stronger and have a higher melting point

43
Q

What is a nanoparticle?

A

It is a really tiny particle, 1–100 nanometres across

44
Q

What is nanotechnology?

A

Nanotechnology is the branch of technology dealing with the making and use of these Nanoparticles

45
Q

Most Nanomaterials are made using nanotechnology, but some nanoscale materials I can naturally or are produced by accident give two examples of this?

A

See spray – the sea produces nanoscale saw particles which are present in the atmosphere.
Combustion – when he was a parent, nanoscale soot particles are produced

46
Q

Nanoparticles are often used to modify the properties of materials give two examples?

A

Going to part with our attitude plastics in sports equipment e.g. tennis rackets golf clubs and golf balls.I make the plastic much stronger and more durable and they don’t add Weight
Silver Nano particles are added to Collymore fibres used to make surgical mask and warm dressing this gives the fibre antibacterial properties

47
Q

What do you mean silver Nanoparticles do?

A

They kill bacteria, making them suitable for wound dressings

48
Q

Why is there controversy over Putting nanoparticles in products?

A

People are wide apart containing an apartment had been made available for the fact that you have been investigated properly as we don’t know that long-term impacts on health will be many people believe that product containing nanoscale particles should be clearly labelled to the consumer can choose whether or not to use them

Chemistry Revision (2 decks)

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