C15

Question 1

E. Rust?

Answer 1

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

Question 2

Ways to prevent rusting?

Answer 2

• covering with:

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

Question 3

D. Galvanised?

Answer 3

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

Question 4

D. Sacrificial protection?

Answer 4

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

Question 5

Corrosion of iron =

Answer 5

rusting

Question 6

When is sacrificial protection often used?

Answer 6

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

Question 7

How does sacrificial protection work?

Answer 7

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.

Question 8

Metals generally alloyed?

Answer 8

gold, copper and aluminium

Question 9

Properties of high carbon steels?

Answer 9

very hard, very brittle

Question 10

Properties of low carbon steels?

Answer 10

softer and easily shaped

Question 11

Properties of stainless steels?

Answer 11

resistant to corrosion

Question 12

What are stainless steels made of?

Answer 12

chromium-nickel steel

Question 13

Properties of polymer depends on…

Answer 13

• monomers used to make it

- conditions used in the reaction

Question 14

D. Thermosoftening polymers?

Answer 14

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

Question 15

D. Thermosetting polymers?

Answer 15

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

Question 16

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

Answer 16

they char

Question 17

What is glass mainly made of?

Answer 17

Sand

Question 18

Conditions used to make LD poly(ethene)

Answer 18

Very high pressures

Question 19

Conditions used to make HD poly(ethene)

Answer 19

using a catalyst at 50 degrees and a slightly raised pressure

Question 20

How is soda glass made?

Answer 20

by heating a mix of sand, limestone and calcium carbonate

Question 21

What is borosilicate glass made from?

Answer 21

sand and boron trioxide

Question 22

Borosilicate glass melting point?

Answer 22

higher then sode-lime glass

Question 23

Properties of ceramics?

Answer 23

• brittle
• insulators
• hard
• resistant to chemical attack

Question 24

How are ceramics made?

Answer 24

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

Question 25

Type of bonds in ceramics

Answer 25

ionic and covalent

Question 26

Structure of ceramics?

Answer 26

- 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

Question 27

Why are ceramic brittle?

Answer 27

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

Question 28

D. Composites?

Answer 28

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

Question 29

Properties of composites of ceramics with polymers as binding material?

Answer 29

tough and flexible (fibreglass)

Question 30

D. The Haber process?

Answer 30

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

Question 31

Raw materials for production of ammonia?

Answer 31

nitrogen in the air | hydrogen - mainly from natural gas (which contains methane)

Question 32

Conditions required for the Haber process?

Answer 32

- iron ctalyst - high temperature ( about 450 degrees C) - high pressure (about 200 atm)

Question 33

what type of reaction is the production of ammonia?

Answer 33

reversible

Question 34

How is ammonia collected?

Answer 34

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

Question 35

E. Haber process?

Answer 35

N2 (g) + 3H2 (g) --> 2NH3 (g)

Question 36

Why arent higher pressures used in the Haber process?

Answer 36

Too expensive and danergous

Question 37

Why arent lower temperatures used for the Haber process?

Answer 37

The rate of reaction would be too slow

Question 38

How is hydrogen produced for the Haber process?

Answer 38

methane + steam --> hydrogen + carbon monoxide

Question 39

What can ammonia be used for in its liquid form?

Answer 39

fertiliser

Question 40

E. Ammonium nitrate fertiliser?

Answer 40

ammonia + nirtic acid ->ammonium nitrate | NH3 (aq) + HNO3 (aq) -> NH4NO3 (aq)

Question 41

What is ammonia used to make?

Answer 41

Nitric acid

Question 42

Ammonium sulphate fertiliser?

Answer 42

ammonia neutratlised with sulphuric acid

Question 43

Ammonium phosphate fertiliser?

Answer 43

ammonia neutralised with phosphoric acid

Question 44

Source of phosphorus?

Answer 44

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

Question 45

Source of potassium?

Answer 45

potassium salts mined from ground for use in fertilisers

Question 46

What do plants need for healthy growth?

Answer 46

nitrogen, potassium and phosphorus

Question 47

D. Formulation?

Answer 47

a mixture that has been designed as a useful product

Question 48

2 potassium compounds used in fertilisers?

Answer 48

potassium chloride | potassium sulfate

Question 49

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

Answer 49

ammonium phosphate | calcium phosphate