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GCSE Chemistry OCR 21st Century (Triple) (9-1) > C4 - Material Choices > Flashcards

C4 - Material Choices Flashcards

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1
Q

What is a polymer?

A

A large molecule formed from smaller

molecules called monomers.

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2
Q

What is meant by the term brittle?

A

Easily broken

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3
Q

What is meant by the terms tension and

compression?

A

● Tension - pulling

● Compression - squashing

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4
Q

When can a material conduct electricity?

A

When it contains charged particles which

are free to move.

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5
Q

What is meant by the term ductile?

A

Ability of a material to be drawn into

wires.

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6
Q

What is meant by the term malleable?

A

If a material is malleable it can be
pressed into shape without breaking or
returning to the original shape.

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7
Q

What are the general properties of glass

ceramics?

A
  • Transparent
  • Strong but brittle
  • Easily moulded into shapes
  • Poor conductors
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8
Q

What are the general properties of clay

ceramics?

A
  • Opaque
  • Soft and malleable
  • Hardened with heat
  • Brittle once hardened
  • Poor conductors
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9
Q

What are the general properties of

polymers?

A 
- Properties can be adapted to suit the
purpose.
- Usually tough and flexible.
- Can be transparent or opaque.
- Poor conductors.
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10
Q

What are the general properties of

metals?

A
  • Shiny
  • Malleable
  • Ductile
  • Good conductors
  • Can form alloys to produce more desirable
    properties
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11
Q

What is a composite material?

A

Contains two or more materials with different
properties.

Typically, there are two components: the
reinforcement (makes up the bulk of the material)
and the matrix (binds the reinforcement together).

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12
Q

Why do composite materials have a wide

range of different properties?

A

As composite materials are made of several
materials, the properties can be tailored to suit
the need of the composite. Different composite
materials contain different reinforcements and
matrixes so the properties vary.

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13
Q

What should be used to construct large

buildings: reinforced concrete or

fibreglass? Why?

A

Reinforced concrete because it is strong
in compression and tension and slightly
flexible.

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14
Q

What should be used to make tennis
rackets: timber or fibre reinforced

plastic? Why?

A

Fibre reinforced plastic because it has a
low density so is lightweight and is
flexible and strong in tension.

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15
Q

What is an alloy?

A

A mixture of a metal and one or more

other elements.

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16
Q

How do the properties of alloys differ to

the properties of metals?

A

Alloys are harder and less malleable. This is
because the uniform rows of atoms in metals
are distorted by different sized atoms and so
the layers are unable to slide over one
another.

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17
Q

How do the uses of alloys differ to the

uses of metals?

A

Alloys are harder so they are often used
rather than metals as they have more
desirable properties.

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18
Q

What is steel?

A

Steel is an alloy of iron.

Three main categories:

  • Mild low carbon steel
  • High carbon steel
  • Stainless steel
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19
Q

How are the properties of mild steel

linked to its uses?

A

Mild steel is malleable and ductile so can
easily be pressed into shape to make car
parts. Galvanising and painting mild steel
makes it resistant to rust.

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20
Q

How are the properties of high carbon

steel linked to its uses?

A

High carbon steel is hard and resistant to
high temperatures so isn’t damaged
when using it as a drill bit.

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21
Q

How are the properties of stainless steel

linked to its uses?

A

Stainless steel is corrosion resistant so it

is suitable for use as cutlery.

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22
Q

What is magnalium?

What is it used for?

A

Magnalium is an alloy of magnesium and
aluminium.

It is lighter and stronger than aluminium and
more resistant to corrosion. It is used for car and
aircrafts.

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23
Q

What is brass?

What is it used for?

A

Brass is an alloy of copper and zinc.

Brass is hard and resistant to corrosion.
It is used for decorative hardware such
as plumbing fittings.

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24
Q

What is addition polymerisation?

A

Addition polymerisation involves the
removal of the C=C double bond from an
alkene to produce a polymer.

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25
Q

What is a repeat unit?

A

A section of the polymer which is
repeated throughout the whole polymer
structure.

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26
Q

Many ethene molecules are joined
together. What is the name of the

polymer that forms?

A

Poly(ethene)

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27
Q

What is condensation polymerisation?

A

Formation of a polymer with the release

of a small molecule such as water.

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28
Q

Compare condensation polymerisation

and addition polymerisation

A

Condensation polymerisation |Addition polymerisation
Needs 2 types of monomer | Only 1 type of monomer
Monomers need two functional groups minimum | Monomers must have C=C bond
Forms 2 products (polymer and many small molecules) | Only forms the polymer

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29
Q

What is an ester?

A

A molecule formed during a condensation
reaction between an alcohol and a
carboxylic acid. One water molecule also
forms during this reaction.

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30
Q

How is a polyester formed?

A

Formed from a condensation reaction
between a dicarboxylic acid (contains 2
COOH groups) and a diol (contains 2 OH
groups).

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31
Q

How many monomers are in one repeat

unit of a polyester?

A

Two

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32
Q

What is a polyamide formed from?

A

Formed from a condensation reaction
between a diamine (contains 2 NH_2
groups) and a dicarboxylic acid (contains
2 COOH groups).

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33
Q

Give a biological example of a polymer

A

DNA

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34
Q

How many different monomers make up

DNA?

A

Four

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35
Q

What are the monomers in DNA called?

A

Nucleotides

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36
Q

Name two more natural polymers and

give their monomers

A
  • Cellulose and starch (monomer is glucose)

- Proteins (monomer is amino acids)

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37
Q

Do the atoms that make up a material
have the same properties as the bulk

material?

A

No

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38
Q

Which three things affect the properties

of a material?

A
  • Types of bonds.
  • Strength of bonds in comparison to
    intermolecular forces.
  • Arrangement of atoms.
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39
Q

Two materials are made from carbon.
Will these materials have the same

properties?

A

No.

  • They may have different bonds that
    have different bond strengths.
  • The atoms may be arranged differently.
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40
Q

What are intermolecular forces?

A

(Relatively weak) forces of attraction

between molecules.

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41
Q

What bonds does carbon form? How

many of these bonds can carbon form?

A

Carbon forms four covalent bonds.

42
Q

What is an organic compound?

A

A compound containing carbon atoms

covalently bonded together.

43
Q

Why are there a large number of

different organic compounds?

A

Because carbon can form homologous
series of similar compounds, chains and
rings.

44
Q

What bonds are found in polymers?

A

Strong covalent bonds.

45
Q

Why do polymers generally have a
higher melting point than other organic

molecules?

A

Polymers are long chained molecules.

Longer chains mean there are more
intermolecular forces between molecules and
so more energy is required to melt polymers.

46
Q

What properties of polymers are affected

by intermolecular forces?

A
  • Melting point
  • Behaviour on heating
  • Hardness
  • Flexibility
47
Q

How are bonds arranged in giant

covalent structures?

A

Many atoms covalently bonded together

in a three-dimensional arrangement.

48
Q

What are allotropes? Give an example

A

Different forms of the same element in
the same state.

E.g. allotropes of carbon are graphite
and diamond.

49
Q

Describe the structure and bonding of

diamond

A
  • Giant covalent structure.
  • Each carbon atom is covalently bonded to
    four other carbon atoms.
  • Regular tetrahedral structure.
  • No free electrons.
50
Q

What are the properties of diamond?

Explain these properties

A
  • Hard due to the 3D structure held by covalent bonds.
  • High melting point because strong covalent bonds
    require a lot of energy to break.
  • Doesn’t conduct electricity as there are no charge
    particles that can move.
51
Q

Describe the structure and bonding of

graphite

A
  • Giant covalent structure.
  • Each carbon atom is covalently bonded to three other
    carbon atoms.
  • Hexagonal layers.
  • Weak attractive forces between layers.
  • There is one delocalised electron per carbon bond.
52
Q

What are the properties of graphite?

Explain these properties

A
  • Electrical conductor because delocalised electrons are free
    to move and carry charge.
  • Soft and slippery (can be used as lubricant) because the
    force between layers are weak so the layers can slide over
    each other.
  • High melting point because strong covalent bonds require a
    lot of energy to break.
53
Q

Describe the bonding in ionic

compounds

A
  • Giant ionic lattice.
  • Oppositely charged ions alternate in a
    regular 3D structure.
  • Electrostatic attraction between the
    oppositely charged ions.
54
Q

Describe and explain the properties of

ionic compounds

A
  • High melting point due to strong ionic bonds
    requiring a large amount of energy to break.
  • Conduct electricity when molten or aqueous
    as the ions are free to move and carry charge.
55
Q

Describe the bonding in metals

A
  • 3D arrangement of layers positive metal
    ions held in a sea of delocalised negative
    electrons.
  • Metallic bonding (electrostatic attraction
    between cations and electrons).
56
Q

Describe and explain the properties of

metals

A
  • High melting point, strong and hard due to strong
    metallic bonds.
  • Malleable and ductile because layers of ions can
    slide across each other.
  • Good conductors because electrons are free to
    move.
57
Q

Describe the bonding of simple

molecular compounds

A
  • Strong covalent bonds between
    atoms.
  • Weak intermolecular forces of
    attraction between small molecules.
58
Q

Describe and explain the properties of

simple molecules

A
  • Low boiling points due to weak intermolecular forces.
  • Liquid or gaseous at room temperature due to low
    melting and boiling points.
  • Don’t conduct electricity as there are no charged
    particles.
59
Q

Describe the bonding in giant covalent

structures

A

Many strong covalent bonds.

60
Q

Describe and explain the properties of

giant covalent structures

A
  • High melting points due to many strong
    covalent bonds.
  • Most do not conduct due to no charged
    particles being present (except graphite).
61
Q

What units are used to compare the
sizes of nanoparticles, atoms and

molecules?

A

Nanometers (nm)

62
Q

What is a nanoparticle?

A

A small structure that is 1-100

nanometers in size.

63
Q

How large are nanoparticles in
comparison to atoms and simple

molecules?

A

Nanoparticles are larger than atoms and

simple molecules.

64
Q

How does the size of nanoparticles affect

their properties and uses?

A

Nanoparticles are tiny so can enter
biological tissues. They can also be used
to form composite materials that have
more beneficial properties.

65
Q

Why would nanoparticles be useful

catalysts?

A

Nanoparticles have a very high surface

area to volume ratio.

66
Q

What is the equation to calculate the

surface area to volume ratio?

A

Surface area to volume ratio = Surface area ÷ Volume

67
Q

Why might nanotubes be used to make

electrical circuits for computers?

A
  • Can conduct electricity.
  • Are very small so take up little space.
  • Lightweight.
68
Q

Why might nanoparticles be used in

sunscreen?

A

Some nanoparticles block UV light.
Nanoparticles absorb easily into the
body so won’t leave white marks on skin.

69
Q

How does the arrangement of atoms in a
tube affect the properties and uses of

nanoparticles?

A

Only 1 atom thick, high tensile strength
and can conduct electricity and heat.

Can be used as molecular sieves or to
form composite materials.

70
Q

What is a fullerene?

A

A fullerene is a molecule made of
carbon, shaped like a closed tube or
hollow ball.

71
Q

Name two fullerenes

A

Graphene

C_60 (buckminsterfullerene)

72
Q

What are the properties of the fullerene

C_60?

A
  • Slippery due to weak intermolecular forces
  • Low melting point
  • Spherical
  • Strong covalent bonds between carbon atoms
    in a molecule
  • Large surface area
73
Q

What are the properties of graphene?

A
  • High melting point due to covalent
    bonding between carbon atoms.
  • Conducts electricity because it has
    delocalised electrons.
74
Q

Why is graphene useful in electronics?

A

It is extremely strong and has delocalised
electrons which are free to move and carry
charge.

It is only one atom thick as it is a single layer of
graphite.

75
Q

What are some of the risks associated

with nanoparticulate materials?

A
  • Little is known about the effects of nanoparticles.
  • May be harmful to health (they could enter the
    bloodstream or be breathed in).
  • May catalyse harmful reactions inside the body.
  • Large surface area to volume ratio may allow toxic
    substances to bind to them and enter the body.
76
Q

What is nanotechnology?

A

The use and control of structures that

are 1-100 nm in size.

77
Q

Calculate the surface area to volume

ratio of a cube with side lengths of 8 nm

A

Surface area of each face = 8 x 8 = 64 nm
6 faces so total surface area = 6 x 64 = 384 nm^2

Volume = 8 x 8 x 8 = 512 nm3
Surface area to volume ratio = 384 ÷ 512 = 0.75

78
Q

Explain oxidation and reduction in terms

of oxygen

A

Reduction is loss of oxygen.

Oxidation is gain of oxygen.

79
Q

When a metal reacts with oxygen, does

reduction or oxidation take place?

A

Oxidation

The metal gains oxygen so is oxidised.

80
Q

What causes corrosion?

A

Oxygen (in air) and water

81
Q

Describe the process of corrosion

A

Reaction of metal with oxygen in the air

to form metal oxide.

82
Q

What is rusting? Write a word equation

for the reaction

A

A reaction between iron or steel with
oxygen and water

Iron + oxygen + water → hydrated iron(III) oxide

83
Q

State two ways corrosion can be

prevented

A

Physical barrier to water and oxygen

Sacrificial protection

84
Q

How can a physical barrier to water and

oxygen be created to prevent corrosion?

A

Coat with plastic

Coat with paint

Coat with oil and grease

85
Q

How can corrosion be prevented by

sacrificial protection?

A

Coat the metal being protected in a more
reactive metal. The more reactive metal
will be oxidised first.

86
Q

What is galvanization?

A

A specific form of sacrificial protection

where iron is coated in zinc.

87
Q

Explain reduction and oxidation in terms

of electrons

A

● Reduction is gain of electrons

● Oxidation is loss of electrons

88
Q

What are the main stages included in a

life-cycle assessment?

A
  • Processing raw materials
  • Manufacture and packaging
  • Transport
  • Use
  • Disposal
89
Q

What factors are considered at each

stage of a life-cycle assessment?

A
  • Use of water and other raw materials
  • Energy use
  • Environmental impact
  • Waste
90
Q

How does obtaining raw materials impact

the environment?

A
  • Uses up limited resources.
  • May damage habitats (mining and
    felling trees).
  • Extraction often requires energy.
91
Q

How does manufacture impact the

environment?

A
  • Land required for factories.
  • Releases pollution into rivers and the
    atmosphere.
92
Q

How does transport of products impact

the environment?

A
  • Requires energy
  • Releases pollution into the
    atmosphere
93
Q

How can a product be disposed?

A
  • Landfill
  • Incineration
  • Recycled
94
Q

How does disposal impact the

environment?

A
  • Land used up for landfill sites.
  • Pollution released during incineration.
  • Recycling needs energy and produces
    waste.
  • Reduced impact if product is reused.
95
Q

What finite resource is used to produce

polymers?

A

Crude oil

96
Q

What are biodegradable and

non-biodegradable materials?

A

Biodegradable: can be decomposed
(broken down) by microorganisms.

Non-biodegradable: can’t be
decomposed by microorganisms.

97
Q

Explain how PET bottles can be recycled

A

PET bottles can be melted down and

remoulded into new products.

98
Q

What factors affect the viability of

recycling a material?

A
  • Finite nature of some resources.
  • Availability of the material to be recycled.
  • Economic and practical issues with collecting and sorting.
  • Removing impurities.
  • Transport and processing energy requirements.
  • Demand for new product.
  • Environmental impact.
99
Q

What are the advantages of recycling

metals?

A 
- Fewer mines and quarries needed to
obtain ores.
- Less noise and dust produced.
- Lower impact on natural habitats.
- Metal ores will last longer.
100
Q

What are the disadvantages of recycling

metals?

A 
- Workers, vehicles and fuel needed to
collect used metal.
- Difficult to sort.
- Sorted metal may need transporting
before it can be processed further.

GCSE Chemistry OCR 21st Century (Triple) (9-1) (6 decks)

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