Metals

Question 1

What is meant by the term “ductility”?

Answer 1

Can be drawn into wires

Question 2

State the properties of metals

Answer 2

• Sonorous
• Malleable
• Ductile
• Conductive (heat & electricity)
• Shiny
• Form basic oxides

Question 3

Name laborotory metals in the order of the reacitivity series, from highest to lowest

Answer 3

• K
• Na
• Ca
• Mg
• Al
• Zn
• Fe
• Pb
• Cu
• Ag
• Au

Question 4

Describe what one would observe when reacting potassium with a) water and b) dilute hydrochloric acid

Answer 4

a) Reacts violently with cold water

b) Reacts violently with dilute acid

Question 5

Describe what one would observe when reacting sodium with a) water and b) dilute hydrochloric acid

Answer 5

a) Reacts vigorously with water

b) Reacts violently with dilute acid

Question 6

Describe what one would observe when reacting calcium with a) water and b) dilute hydrochloric acid

Answer 6

a) Reacts slowly with water

b) Reacts rapidly with dilute acid

Question 7

Describe what one would observe when reacting magnesium with a) water and b) dilute hydrochloric acid

Answer 7

a) Reacts slowly with boiling water

b) Reacts very fast with dilute acid

Question 8

Describe what one would observe when reacting aluminium with a) water and b) dilute hydrochloric acid

Answer 8

a) Reacts violently with boiling water to form a protective layer
b) Reacts very fast with dilute acid

Question 9

Describe what one would observe when reacting zinc with a) water and b) dilute hydrochloric acid

Answer 9

a) Reacts slowly with boiling water

b) Reacts slowly with dilute acid

Question 10

Describe what one would observe when reacting iron with a) water and b) dilute hydrochloric acid

Answer 10

a) No reaction

b) Reacts very slowly with dilute acid

Question 11

Why is zinc a popular galvanising substance for iron sheets?

Answer 11

Also forms a protective layer, much like aluminium does

Question 12

State where sodium (Na) is naturally found, and the method of extraction

Answer 12

Found in rock salt, extracted by electrolysis of molten salt (Basically wat Hanno wil doen…)

Question 13

State where zinc (Zn) is naturally found, and the method of extraction

Answer 13

Zinc blende

- Heating with oxygen to form oxide, then heated with carbon

Question 14

State where copper (Cu) is naturally found, and the method of extraction

Answer 14

Copper pyrites

- Heating with oxygen to form oxide, then heated with carbon

Question 15

State where gold (Au) is naturally found, and the method of extraction

Answer 15

Dissolved in potassium cyanide an reduced by zinc

Question 16

Write three balanced chemical equasions for the extraction of zinc from ZnS

Answer 16

2Zns + 3O2 -> 2ZnO 2SO2
ZnO + C -> Zn + CO
2CO + O2 -> 2CO2

Question 17

Write 5 balanced chemical equasions for the extraction of iron from Fe2O3

Answer 17

CaCO3 -> CaO + CO2
CaO + SiO2 -> CaSiO3 (Calcium silicate)
C + O2 -> CO2
CO2 + C -> 2CO
Fe2O3 + 3CO -> 2Fe + 3CO2

Question 18

State the uses of alloys of copper

Answer 18

• Coins
• Brass instruments (zinc)
• Bronze statues (tin)

Question 19

Why is copper suitable for producing water pipes?

Answer 19

Copper can withstand water pressure and also does not corrode (unreactive)

Question 20

State some uses of aluminium

Answer 20

• Aircraft parts (light and malleable) [Duralumin with copper]
• Overhead electricity cables
• Pots and pans

Question 21

Why is zinc used to galvanise iron sheets

Answer 21

Zinc is more reactive and therefore does not let the iron come into contact with oxygen, which would cause rust