Electrolysis

Question 1

Electrolysis

Answer 1

ionic compound, in the aqueous / molten state is made to decompose by the passage of electricity

Question 2

Electrolyte

Answer 2

ionic compound which can conduct electricity in aqueous / molten state and is decomposed by it

Question 3

Applications of electrolysis

Answer 3

• purification / refining of metals
• electroplating
• extraction of metals

Question 4

Importance of electroplating

Answer 4

• improve physical properties of metals
• increase a metal’s resistance to corrosion

Question 5

Copper plating object

Answer 5

• cathode : object
• anode : pure copper
• electrolyte : CuSO4(aq)

Question 6

Silver plating an object

Answer 6

• cathode : object
• anode : pure silver
• electrolyte : Ag(NO3)2

Question 7

Uses of aluminium

Answer 7

• aluminium paint
• door & window frames
• electrical cables ; high electrical conductivity & low density
• make alloys used to make aircraft & racing bicycles ; low densitites
• make cooking utensils ; protective oxide layer ; prevents rusting ; good conductor of heat

Question 8

Anodising

Answer 8

oxide layer of aluminium increased to make it more resistant to corrosion

Question 9

Iron ore

Answer 9

Haematite

Question 10

Aluminium ore

Answer 10

Bauxite

Question 11

Main impurities present inhaematite

Answer 11

• silica
• silicon
• carbon
• sulfur
• phosphorous

Question 12

Waste gases from blast furnace

Answer 12

• N2
• CO
• CO2
• SO2

Question 13

Importance of recycling metals

Answer 13

• reduce environmental impact
• create jobs
• preserve metallic ores