C15 Flashcards

1
Q

E. Rust?

A

iron + oxygen+water -> hydrated iron (111) oxide

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2
Q

Ways to prevent rusting?

A
  • covering with:

paint, oil, grease or plastic ,a less reactive metal, a more reactive metal

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3
Q

D. Galvanised?

A

Iron or steel objects that are protected from rusting by a layer of zinc metal on their surface

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4
Q

D. Sacrificial protection?

A

An effective way to prevent rusting; a metal more reactive then iron (zinc or magnesium) is attached to or coated on an object

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5
Q

Corrosion of iron =

A

rusting

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6
Q

When is sacrificial protection often used?

A
  • when coating is likely to be scrated
  • in harsh conditions (eg. iron legs of a pier)
  • underground pipes
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7
Q

How does sacrificial protection work?

A

Zinc is more reactive then iron, because is a stronger reducing agent, so it has a stringer tendency to loose electrons and form positive ions. so water/oxygen reacts with zinc instead of the iron.

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8
Q

Metals generally alloyed?

A

gold, copper and aluminium

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9
Q

Properties of high carbon steels?

A

very hard, very brittle

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10
Q

Properties of low carbon steels?

A

softer and easily shaped

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11
Q

Properties of stainless steels?

A

resistant to corrosion

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12
Q

What are stainless steels made of?

A

chromium-nickel steel

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13
Q

Properties of polymer depends on…

A
  • monomers used to make it

- conditions used in the reaction

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14
Q

D. Thermosoftening polymers?

A

these soften easily when heated and then reset when cooled - as they are made of individual polymer chains that are easily seperated

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15
Q

D. Thermosetting polymers?

A

These do not melt when they are heated as they have strong covalent bonds between polymer chains

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16
Q

What happens to thermosetting polymers if they are very strongly heated?

A

they char

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17
Q

What is glass mainly made of?

A

Sand

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18
Q

Conditions used to make LD poly(ethene)

A

Very high pressures

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19
Q

Conditions used to make HD poly(ethene)

A

using a catalyst at 50 degrees and a slightly raised pressure

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20
Q

How is soda glass made?

A

by heating a mix of sand, limestone and calcium carbonate

21
Q

What is borosilicate glass made from?

A

sand and boron trioxide

22
Q

Borosilicate glass melting point?

A

higher then sode-lime glass

23
Q

Properties of ceramics?

A
  • brittle
  • insulators
  • hard
  • resistant to chemical attack
24
Q

How are ceramics made?

A

by forming shapes out of wet clay and then heating them in a furnace to about 1000 degrees

25
Q

Type of bonds in ceramics

A

ionic and covalent

26
Q

Structure of ceramics?

A
  • ions and atoms form giant structures that form layers
  • when wet, water gets in between layers making them slimy
  • when heated in furnace, water is driven out and strong bonds form between layers
27
Q

Why are ceramic brittle?

A

a sharp blow can distort the layers in the structure so that ions with like charges are adjacent and repel each other

28
Q

D. Composites?

A

materials made of 2 or more different materials, containing a matrix/binder surrounding and binding together fibres or fragments of another material which acts as a reinforcement

29
Q

Properties of composites of ceramics with polymers as binding material?

A

tough and flexible (fibreglass)

30
Q

D. The Haber process?

A

way of turning nitrogen in air into ammonia - plants cant use nitrogen gas

31
Q

Raw materials for production of ammonia?

A

nitrogen in the air

hydrogen - mainly from natural gas (which contains methane)

32
Q

Conditions required for the Haber process?

A
  • iron ctalyst
  • high temperature ( about 450 degrees C)
  • high pressure (about 200 atm)
33
Q

what type of reaction is the production of ammonia?

A

reversible

34
Q

How is ammonia collected?

A

the gases are cooled so that ammonia liquefies and the unused gases can be collected and reused

35
Q

E. Haber process?

A

N2 (g) + 3H2 (g) –> 2NH3 (g)

36
Q

Why arent higher pressures used in the Haber process?

A

Too expensive and danergous

37
Q

Why arent lower temperatures used for the Haber process?

A

The rate of reaction would be too slow

38
Q

How is hydrogen produced for the Haber process?

A

methane + steam –> hydrogen + carbon monoxide

39
Q

What can ammonia be used for in its liquid form?

A

fertiliser

40
Q

E. Ammonium nitrate fertiliser?

A

ammonia + nirtic acid ->ammonium nitrate

NH3 (aq) + HNO3 (aq) -> NH4NO3 (aq)

41
Q

What is ammonia used to make?

A

Nitric acid

42
Q

Ammonium sulphate fertiliser?

A

ammonia neutratlised with sulphuric acid

43
Q

Ammonium phosphate fertiliser?

A

ammonia neutralised with phosphoric acid

44
Q

Source of phosphorus?

A

Phosphate rock, which is mined and treated with acids to form fertiliser

45
Q

Source of potassium?

A

potassium salts mined from ground for use in fertilisers

46
Q

What do plants need for healthy growth?

A

nitrogen, potassium and phosphorus

47
Q

D. Formulation?

A

a mixture that has been designed as a useful product

48
Q

2 potassium compounds used in fertilisers?

A

potassium chloride

potassium sulfate

49
Q

phosphate rock is mined and treated with acids to form compounds….

A

ammonium phosphate

calcium phosphate