C2 Flashcards

1
Q

Definition of melting point?

A

The temperature a which a solid turns into a liquid

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2
Q

What is density?

A

Mass of a given volume of the material

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3
Q

When should outliers be discarded?

A

Only if there was an error in the measurement.

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4
Q

How do you get the true value?

A

By calculating the mean

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5
Q

Name 3 properties of metals

A

Shiny, malleable, and electrical conductors

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6
Q

Can all metals conduct electricity?

A

YES!!!

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7
Q

What are Natural materials?

A

Materials from living things which require little processing.

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8
Q

Give 2 examples of natural materials?

A

Silk and wool

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9
Q

What are Synthetic materials?

A

Materials that are manufactured by chemical reactions using raw materials.

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10
Q

Why have synthetic materials replace natural materials?

A
  1. Some natural materials are in short supply
  2. They can be designed to give particular properties
  3. They are cheaper and can be made in quantity needed
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11
Q

What are hydrocarbons made of?

A

Hydrogen and Carbon atoms

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12
Q

What is crude oil made up of ?

A

A Mixture of hydrocarbons

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13
Q

How do you seperate crude oil?

A

Using fractional distillation

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14
Q

How does FD seperate crude oil?

A

It seperates them using boiling points

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15
Q

As the hydrocarbon chain length increases…

A

The forces between these molecules increase.

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16
Q

Why do larger molecules have higher boiling points

A

Because they need more energy to break intermolecular forces

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17
Q

The smaller the molecule chain…

A

the lower the boiling point.

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18
Q

What is a polymer?

A

A chain of monomers

19
Q

What is the process that makes a polymer?

A

Polymerisation

20
Q

When are the forces strongest?

A

The closer they are, the stronger they are.

21
Q

The stronger the force…

A

The more energy is needed to seperate the molecules and the higher the melting point.

22
Q

What does LDPE stand for?

A

Low density polyethene

23
Q

What are the properties of LDPE ?

A

LDPEs have BRANCHES which make the intermolecular forces weak

24
Q

What are the properties of HDPE?

A

HDPEs Dont have branches which makes the intermolecular forces strong

25
Q

Give an example of LDPE and HDPE?

A

Carrier bags and Water pipes

26
Q

What do plasticisers do?

A

Plasticisers make polymers softer by keeping the chains apart and weakening the forces between them

27
Q

What can soften when heated and be moulded into shape.

A

Thermoplastics

28
Q

What contains cross-links and cannot soften when heated

A

Thermosetting

29
Q

How can Crytallinity be increased?

A

By removing branches, making the chain as flat as possible

30
Q

What are Nanoparticles?

A

Material containing up to a thousand atoms

31
Q

Name 3 ways in which nanoparticles occur?

A
  1. Naturally ie seasalt spray
  2. by accident, in solid particulate when fuels burn
  3. can be designed in laboratories
32
Q

What are structures made up of nanoparticles measured in?

A

Nanometres (nm)

33
Q

Why are nanoparticles effective catalysts?

A

Because they have a large surface area. Increasing the surface area provides more sites for reactions to take place.

34
Q

What type of nanoparticle kills bacteria?

A

Silver nanoparticles

35
Q

What are Titanium oxide nanoparticles used in?

A

Sunscreen as the make it transparent and absorb UV light

36
Q

What do you get when you mix Nanoparticles with metals or ceramics?

A

Composites

37
Q

Why would add nanoparticles to plastic sports equipment or tennis balls?

A

Adding them to sports equipment makes it stronger and makes tennis balls bounce longer

38
Q

What is Nanotechnology?

A

The science of making and using nanoparticles

39
Q

Why are Silver nanoparticles dangerous?

A

They can be washed out of clothing, get into the sewage system and kill good bacteria.

40
Q

TRUE OR FALSE: Nanoparticles cant pass through the skin into blood?

A

FALSE, They can and the effects are unknown.

41
Q

Why are people afraid of nanoparticles in the air?

A

Because if breathed in , they could cause lung or brain damage.

42
Q

Why are some not afraid of nanoparticles?

A

Because they occur naturally like in soot and volcanic dust

43
Q

In general why are people scared?

A

Because we don’t know enough about nanoparticles.