Metals

Question 1

Describe how metals occur naturally

Answer 1

Combined with other elements in compounds called ores

Question 2

Name the ore in which aluminium occurs naturally, also state the chemical formula for the ore

Answer 2

Bauxite

Al2O3

Question 3

Name the ore in which zinc occurs naturally, also state the chemical formula for the ore

Answer 3

Zinc blende

ZnO

Question 4

Name the ore in which uranium occurs naturally, also state the chemical formula for the ore

Answer 4

Pitch blende

UO (uranium oxide)

Question 5

Name the ore in which iron occurs naturally, also state the chemical formula for the ore

Answer 5

Haematite

Fe2O3

Question 6

Name the ore in which tin occurs naturally, also state the chemical formula for the ore

Answer 6

Casserite

Sn02

Question 7

Name the ore in which copper occurs naturally, also state the chemical formula for the ore

Answer 7

Copper pyrites

Cu2S

Question 8

Name the ore in which gold occurs naturally, also state the chemical formula for the ore

Answer 8

Gold occurs naturally pure, with the chemical formual Au

Question 9

State four uses of aluminium

Answer 9

• Pans and food containers, utensils
• Overhead electricity cables
• Aircraft parts
• As an alloy when mixed with copper

Question 10

Describe why aluminium is a suitable metal for the manufacturing of aircraft parts

Answer 10

Light weight metal and does not corrode

Question 11

State three uses of copper

Answer 11

• Electrical wiring
• In water pipes
• Alloys

Question 12

Name the two metals present in duralium

Answer 12

Copper, aluminium

Question 13

Name the two metals present in brass

Answer 13

Copper, zinc

Question 14

Name the two metals present in bronze

Answer 14

Copper, tin

Question 15

State why copper is a suitable metal for using in water pipes

Answer 15

Copper is unreactive and does not corrode easily

Question 16

State two uses of zinc

Answer 16

• Galvanising

- Alloys (brass)

Question 17

Name a use of iron, and state why iron is suitable for this use

Answer 17

Structural material, strong and malleable

Question 18

Name one use of tin, and state why tin is suitable for this use

Answer 18

Coating steel cans, unreactive and non-toxic

Question 19

Fully describe the extraction process of aluminium

Answer 19

Aluminium is a reactive metal and needs to undergo electrolysis to be extracted. During electrolysis, bauxite is dissolved in molten cryolite, forming the electrolyte. Carbon or graphite plates act as the anode, also as the cathode, at which molten aluminium accumilates. Aluminium ore is dissolved in croylite in order to lower the melting point of the ore. Oxygen bubbles to the top. (Probeer maar self sin maak hiervan..)

Question 20

Name the substances that is contained within the charge of a blast furnace

Answer 20

• Haematite
• Coke (Pure carbon)
• Limestone

Question 21

Describe the 6 reactions that take place during the extraction of iron in a blast furnace

Answer 21

1. The coke burns
C + 02 = C02
2. Coke reduces carbon dioxide
C02 + C = 2C0
3. Carbon monoxide reduces iron ore
Fe2O3 + 3C0 = 2Fe + 3CO2
4. Carbon reduces iron ore
2Fe203 + 3C = 4Fe + 3CO2
5. Limestone decomposes
CaCO3 = CaO + CO2
6. Slag forms
CaO + SiO2 (sand) = CaSiO3

Question 22

Name one use for slag

Answer 22

Road building

Question 23

Describe the extration of copper

Answer 23

The ore is roasted in air

Question 24

Describe the extraction of sodium

Answer 24

Electrolysis of molten sodium chloride

Question 25

Describe the extraction of zinc

Answer 25

Roasting in air

Question 26

Describe the term “alloy”

Answer 26

A mixture of metals, often to change the properties of metals and make them more usefull

Question 27

Describe two ways in which rusting or iron can be prevented

Answer 27

• Galvanising (covering with a zinc layer)

- Painting