topic 4 - extracting metals and equilibria

state the properties of metals

• malleable

• electrical conductor

• high melting/boiling point

• ductile

• shiny

• dense

explain why metals are malleable

layers of metal cations can slide over each when force is applied

explain why metals are electrical conductors

• metal layers contain sea of delocalised electrons

• which are capable of moving and carrying charge

explain why metals have high melting/boiling points

• large amount of energy needed to overcome

• strong electrostatic forces of attraction

• between metal cations and delocalised electrons

explain the differences between metals and non-metals

• conductivity - metals can conduct and most non-metals can’t

• boiling/melting points - metals have high melting points and most non-metals have low melting points

explain what a displacement reaction is

• redox reaction

• as both oxidation and reduction occur

state what a redox reaction is

a reaction where both oxidation (loss of electrons) and reduction (gain of electrons) occurs

state the metal reactivity series

1. potassium

2. sodium

3. calcium

4. magnesium

5. aluminium

6. carbon

7. zinc

8. iron

9. tin

10. lead

11. hydrogen

12. copper

13. silver

14. gold

15. platinum

state which metals react with water

• potassium

• sodium

• calcium

state which metals react with acids

1. magnesium

2. aluminium

3. zinc

4. iron

5. tin

6. lead

recall how and where metals are found

• extracted from ores in the earth’s crust

• unreactive metals are found as unreacted elements

explain what oxidation is

• gain of oxygen

• loss of electrons

explain what reduction is

• loss of oxygen

• gain of electrons

recall what the extraction of metals involves

reduction of metal ores

state which metals are extracted from their ores by heating with carbon

• zinc

• iron

• tin

• lead

state which metals are extracted from their ores by electrolysis

• potassium

• sodium

• calcium

• magnesium

• aluminium

explain why specific metals are extracted from their ores by heating with carbon based on their relative reactivity

• zinc, iron, tin and lead are extracted using carbon

• as they are less reactive than carbon

• so the carbon can displace the metal from its ore

explain why specific metals are extracted from their ores by heating with carbon based on cost of extraction

• this process requires less energy for extraction

• keeping costs lower

explain why specific metals are extracted from their ores by electrolysis based on their relative reactivity

• potassium, sodium, calcium, magnesium and aluminium are extracted using electrolysis

• as they are more reactive than carbon

• and therefore carbon cannot displace it from its ore

evaluate bioleaching as a method of metal extraction

• avoids significant environmental damage caused by traditional methods including mining

• process is very slow

• can extract metals from mining waste

evaluate phyto mining as a method of metal extraction

• avoids significant environmental damage caused by traditional methods including mining

• process is very slow

• can extract metals from mining waste

recall what oxidation of metals causes

corrosion

explain how the exclusion of oxygen prevents the rusting of iron

• iron, water and oxygen react together to make hydrated iron oxide

• iron oxide is rust

• without oxygen, iron oxide could not be formed

explain how the exclusion of water prevents the rusting of iron

• iron, water and oxygen react together to make hydrated iron oxide

• iron oxide is rust

• without water, iron oxide could not be formed

explain how sacrificial protection prevents the rusting of iron

• if iron is in contact with a more reactive metal, the more reactive metal will oxidise

• this means the iron will not rust as it won’t oxidise

evaluate the advantages of recycling metals

• less mining for raw materials - preserves environment

• preserves supply of raw materials

• more economical to recycle instead of mine for new material as it takes up less energy

explain how electroplating can be used to improve the appearance of metal objects

• electroplating is when a metal object is covered in a thin layer of another metal

• this thin layer of metal can be used to improve the appearance of the object

• e.g. make it shiny

explain how electroplating can be used to improve the resistance to corrosion of metal objects

• electroplating is when a metal object is covered in a thin layer of another metal

• the layer of metal provides a physical barrier to oxygen and water, ensuring iron oxide (rust) cannot form

explain why converting pure metals into alloys increases the strength of the metal

• an alloy is when a metal is added to a pure metal in order to increase strength

• the added metal disrupts the regular structure and arrangement of metal cations and delocalised electrons

• this means the layers of metal cannot slide over each other, increasing the strength of the metal

explain why iron is alloyed with other metals to produce alloy steels

• pure iron is a very soft material

• when another metal is added, steel alloy is created

• the steel alloy is stronger than the pure iron

state the properties of aluminium

• corrosion resistant

• good conductor

• strong (when alloyed)

• low density

explain how the properties of aluminium are related to its uses

• corrosion resistant - cans and aircrafts

• good conductor - pots, pans and power cables

• strong (alloy form) - pots and pans

state the properties of copper

• malleable

• ductile

• good conductor

• corrosion resistant

• attractive colour

explain how the properties of copper are related to its uses

• attractive colour - decorative goods

• corrosion resistant - water pipes

• ductile - electrical wires

state the properties of gold

• malleable

• attractive colour

• corrosion resistant

• shiny

explain how the properties of gold are related to its uses

• malleable - jewellery

• attractive colour - jewellery

• shiny - jewellery

• corrosion resistant - jewellery

state the properties of magnalium

• strong

• low density

• corrosion resistant

explain how the properties of magnalium are related to its uses

• corrosion resistant - aircraft parts

• strong - aircraft parts

state the properties of brass

• corrosion resistant

• malleable

• ductile

• good conductor

explain how the properties of brass are related to its uses

• corrosion resistant - plumbing fittings

• good conductor - electrical wires