Topic 9 (RVEISION

Question 1

Uses and properties: Aluminium

Answer 1

• Low density
• Corrosion Resistense
• Electrical Conductor
  EX: wires, aircrafts, cables

Question 2

Uses and properties: Copper

Answer 2

• Electrical conducter
• Thermal conductor
  EX: wires, cooking

Question 3

Uses and properties: Zinc

Answer 3

• Strong
• Ductile
• Reactive Metal
  EX: Brass, galavanising

Question 4

Alloy

Answer 4

Mixture of a metal with other elements
- Less malleable
Different sized ions in the lattice that make it harder or layers to slide

Question 5

Composition of Alloys: Steel

Answer 5

Iron + Carbon

Question 6

Composition of Alloys: Stainless

Answer 6

Iron + Carbon + Chromnium + Nickel

Question 7

Composition of Alloys: Brass

Answer 7

Copper + Zinc

Question 8

Composition of Alloys: Bronze

Answer 8

Copper + Tin

Question 9

Properties of stainless steel

Answer 9

Resists corrosion, hard (Ex: Cutlery)

Question 10

Corrosion

Answer 10

name given to the process that takes place when metals and alloys react with oxygen, and sometimes water.

Question 11

Two substances, which are both necessary for the rusting of iron, are:

Answer 11

 water, or the water in air
 oxygen, or the oxygen in air

Question 12

Rusting will happen faster if what? why?

Answer 12

salt water is used because it contains ions which can
transfer electrons and speed up the reaction.

Question 13

Rusting can be prevented, or slowed down by a variety of methods.

Answer 13

Different methods work in different situations, there is no single best way of preventing rusting

Question 14

Rust Preventation: Car bodies
Bridges

Answer 14

• Paint
  if the paint is scratched, the
  iron beneath it starts to
  rust.

Question 15

Rust Preventation: Moving parts of
machinery
Bicycle chain

Answer 15

• Oil or Grease
• prevents water getting to
  the iron

Question 16

Rust Preventation: Steel girders
used in bridges
and buildings

Answer 16

-Galvanising
- long lasting and easy to apply

Question 17

Rust Preventation: Freezers

Answer 17

• Coating with plastic - PVC is used to
  coat steel preventing it from being in
  contact with oxygen and water
• lasts a long time

Question 18

Rust Preventation: Food can

Answer 18

• Tin plating - steel is coated with a layerof tin
• tin does not easily corrode
  and is not poisonous. Zinc
  cannot be used for food
  cans because zinc and its
  compounds are poisonous

Question 19

Rust Preventation Ships

Answer 19

• Sacrificial protection
• allowing a more reactive
  metal to corrode instead

Question 20

Rust Preventation Oil rigs

Answer 20

• Cathodic protection
• using a power source to get
  another metal to corrode
  instead

Question 21

Galavanising

Answer 21

Where iron in coated with a surface layer of zinc. Zinc is used to protect iron or steel fromm rusting as its impermable to oxygen and water preventing it form coming in contact with iron.

Question 22

Sacrifical Protection

Answer 22

Sacrificial protection is a method used to prevent iron from rusting by coating it with a more reactive metal, like zinc or magnesium. If the coating gets scratched and exposes the iron, the more reactive metal (zinc, for example) reacts with water and oxygen instead of the iron. Zinc loses electrons, which flow to the iron and stop it from rusting.

Question 23

Cathodic Protection

Answer 23

Cathodic protection is a method used to prevent metal corrosion, like rusting. It works by supplying electrons to the metal (such as steel), which prevents it from losing electrons and oxidizing (rusting).

Question 24

What happens in the anode at cathodic protection.

Answer 24

At the anode, electrons are lost (oxidation), and substances like chlorine or oxygen gas are formed.

Question 25

What happens in the cathode at cathodic protection.

Answer 25

These electrons travel through an external circuit to the cathode, where they are supplied to the metal.
The metal (e.g., steel) at the cathode doesn’t rust because it’s constantly receiving electrons, preventing oxidation.

Question 26

Difference between cathodic and sacrifical protection

Answer 26

Sacrificial protection uses a more reactive metal (like zinc) as the anode, which corrodes instead of the iron or steel.
Cathodic protection uses an inert metal (like platinum) as the anode, supplying electrons to protect the iron or steel from corrosion.

2) Sacrificial protection does not need electricity, but cathodic protection
requires electricity.

Question 27

Ore of haematite: Compound and processed by:

Answer 27

iron (III) oxide
Carbon reduction

Question 28

Ore of Bauxite: Compound and processed by:

Answer 28

Aluminium Oxide
Electrolysis

Question 29

What are the 2 methods of extracting ores based on reactivites?

Answer 29

1.Metals less reactive than carbon can be extracted in a blast furnace using carbon reduction.
2. Metals more reactive than carbon are extracted using electrolysis.

Question 30

When is carbon reduction used?
And what are the reducing agents?

Answer 30

For metals less reactive than carbon (zinc to platinum), carbon reduction is used to
extract the metal. Carbon, or carbon monoxide is a reducing agent, which reduces
the metal ions in the compound to metal atoms.

Question 31

Haematite?

Answer 31

is a mixture of iron(III) oxide and impurities, mainly sand (SiO2).

Question 32

Coke?

Answer 32

is a pure form of coal - it contains mainly carbon

Question 33

Limestone?

Answer 33

is a rock from the ground - it contains mainly calcium carbonate

Question 34

What enterce from the top of the furnace and oleaves during carbon reduction?

Answer 34

Haematite, coke and limestone enter at the top of the furnace.
Carbon dioxide gas and nitrogen gas leave the furnace as waste gases.

Question 35

Reactions: Coke (combustion to produce heat and carbon monoxide)

Answer 35

C + O2 = CO2
CO2 + C = 2CO

Question 36

Reactions: Limestone (thermal decomposition to form calcium oxide)

Answer 36

CaCO3 = CaO + CO2

Question 37

Reactions Haematite (reduction of iron(III) oxide)

Answer 37

Fe2O3 + 3CO = 2Fe + 3CO2
2Fe2O3 + 3C = 4Fe + 3CO2

Question 38

Silicon(IV) oxide, an acidic impurity is removed by basic calcium oxide forming slag,
calcium silicate.

Answer 38

CaO + SiO2  CaSiO3

Question 39

What is slag used for

Answer 39

used to make roads and cement; as well as electronic chips.