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Y9 FLASHCARDS > CHEMISTRY 9E > Flashcards

CHEMISTRY 9E Flashcards

1
Q

What are ceramics?

A

They are a range of hard, durable, non- metallic materials that are generally unaffected by heat

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2
Q

How are ceramics formed?

A

Often formed by heating and then cooling.

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3
Q

Examples of ceramics?

A

Ceramics include traditional bricks, china and glass as well as more modern materials used to make artificial bones and protective coverings for space crafts

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4
Q

Physical properties of ceramics?

A
  • hard, stiff, strong when compressed, and brittle
  • high melting points and heat resistant
  • good insulators of heat and electricity
  • very unreactive
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5
Q

What happens when clay is heated?

A

Chemical reactions occur and new compounds, such as China and porcelain, are formed

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6
Q

What happens during cooling?

A

During cooling, crystals form and bind together in the ceramic.

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7
Q

What does the size of the crystals depend on?

A

The size of the crystals depends on the speed of cooling. Slower cooling produces larger crystals.

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8
Q

Why does slower cooling produce larger crystals?

A

Because the atoms have more time to form a grid-like lattice structure. This is similar to the formation of large crystals in granite when magma cools slowly

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9
Q

What happens in a lattice structure?

A

There are a large number of atoms, in a fixed regular lattern, all joined to each other by strong bonds.

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10
Q

Why are ceramics stiff?

A

One reason is because there are so many atoms bonded to each other, with strong bonds, in a rigid structure. This high strength of the bonds is the reason why ceramics have such high melting points.

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11
Q

Why is glass slightly different than other ceramics?

A

It is different because its atoms do not form a regular pattern, although the atoms are still held together by many strong bonds.

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12
Q

What is porcelain used for?

A

For cable supports on electricity pylons as it does not conduct electricity

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13
Q

What is China used for?

A

For tableware, as it is strong and a heat insulator

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14
Q

Natural Polymers?

A
  • Rubber
  • Wool
  • DNA
  • Proteins
  • Starch
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15
Q

Synthetic Polymers?

A 
Synthetic rubber
Poly vinyl 
Poly ethene
Poly propene 
Nylon
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16
Q

Rubber properties?

A

Soft and sticky when hot

Hard and brittle when cold

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17
Q

Why are polymers elastic?

A

They are elastic because the long coiled molecules go back to their original shape when streched

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18
Q

How are polymers formed?

A

They are formed by joining together many small molecules called monomers

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19
Q

What happens if crosslinks are formed between chains?

A

It makes the polymer harder and less easy to melt

20
Q

What does Vulcanisation do?

A

It uses sulfur to form cross-links in rubber molecules

21
Q

What is poly(ethene) used for?

A

It is used for plastic bags and buckets as it is strong, flexible and durable

22
Q

Characteristics of Polymers?

A

They are generally strong, flexible, non conductors of heat and electricity, durable and unreactive

23
Q

What is poly(vinyl chloride) used for?

A

It is used for covering electrical cables as it is flexible, strong and a non conductor of electricity

24
Q

What are most synthetic polymers made of?

A

Raw materials obtained from crude oil

25
Q

What is a composite material?

A

Composite materials are combinations of two or more materials, with some of the properties of each

26
Q

How are many composite materials made by?

A

They are made by mixing fibres into a liquid resin which then sets hard. Different types of fibres and resins produce different composite materials with different properties and uses

27
Q

What is concrete used for?

A

Concrete is a composite material that has been used for thousands of years, it is used for large structures because it is strong and durable.

28
Q

What is concrete made of?

A

It is made from a mixture of cement, sand, aggregate (crushed rocks) and water

29
Q

Why are composite materials useful?

A

They are useful because they combine the properties of all the materials they are made from

30
Q

What happens in safety glasses?

A

Layers of glass are combined with clear polymer

31
Q

What is an exothermic reaction?

A

The ones that transfer energy to the surroundings so the temperature of the surroundings rises

32
Q

What is an endothermic reaction?

A

A reaction that transfers energy from the surroundings so the temperature of the surroundings falls

33
Q

Structure of a composite material?

A

Many composite materials cantain fibres embedded in a matrix or resin

34
Q

Thermal decomposition reaction of cement?

A

CaCo3. ->. CaO. +. CO2
Calcium carbonate. calcium oxide+ carbon dioxide

35
Q

What is the word equation for combustion of carbon?

A

Oxygen + Carbon -> carbon dioxide + water

36
Q

What is the word equation for combustion of sulfur?

A

Oxygen + Sulfur -> Sulfur Dioxide + Water

37
Q

Word equation for combustion of nitrogen?

A

Oxygen + Nitrogen -> Nitrogen Oxide + Water

38
Q

Incomplete combustion of Carbon?

A

Oxygen + Carbon -> Carbon Monoxide + Water

39
Q

Burning fissil fuels provides the energy needed to make materials but is also linked to?

A
  • Acid Rain from production of sulfur dioxide
  • Increase in carbon dioxide levels and the greenhouse effect
  • soot dirtying buildings and damaging health
40
Q

How does acid rain work?

A

Sulfur dioxide and nitrogen oxides, are acidic gases that dissolve in clouds and fall as acid rain

41
Q

What causes acid rain?

A
  • Sulfur dioxide, caused by sulfur impurities in fuels, can form acid rain
  • Nitrogen oxides, caused by combustion temperatures, can also form acid rain.
42
Q

Problems with making and using materials?

A
  • Toxic substances released in waste get into food chains
  • As large animals eat lots of smaller animals, toxin levels increase (biogmanification) and can reach harmful levels in humans.
  • Non-biodegradable polymer waste causes pollution problems and dangers to animals for years
43
Q

Solutions to making and using materials?

A
  • Removal of sulfur from fuels
  • Reduction in the use of fossil fuels and use of more renewable energy sources
  • Control of hazardous waste from factories
  • Use of biodegradable polymers, which break down in the soil, so they disappear quicker
44
Q

Key Features of recycling materials to use again?

A
  • Reduces our use of landfill sites
  • Reduces the need to burn fossil fuels
  • Reduces pollution from manufacturing process
  • Saves our resources of raw materials, e.g. metal ores for metals and wood for paper
45
Q

Examples of materials that can be recycled?

A

Metals - by separating and melting
Glass - by separating colours and melting
Polymers - by using recycle labels
Paper- by removing ink and adding water to make a pulp
Concrete- by crushing and grading

46
Q

What is an example of and Exothermic Reaction?

A

Combustion reactions, because it transfers energy into the surroundings and increase the temperatures

47
Q

Example of an Endothermic reaction?

A

Decomposition reactions because they transfer energy from the surroundings and therefore decrease the temperature

Y9 FLASHCARDS (10 decks)

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