Chapter 10

Question 1

Physical properties of metals

Answer 1

high conductivity (heat and electricity), malleable, ductile, high melting and boiling point

Question 2

Chemical properties of metals

Answer 2

metals react with acids to produce salt and hydrogen, a displacement reaction occurs with acids, and metals react with oxygen to produce a metal oxide

Question 3

Why are alloys more used than pure metals?

Answer 3

Pure metals are more malleable and less tough than alloys. This is because the uniform layers can slide over each other while strange different sized atoms in alloys make it more difficult for the layers to slide across each other, making it less malleable.

Question 4

Identify the difference in alloy diagrams and pure metal diagrams

Answer 4

idk just find it out for yourself

Question 5

Reactivity series and their reactions

Answer 5

potassium, sodium, lithium, calcium, magnesium, aluminium, (carbon), zinc, iron, (hydrogen), copper, silver and gold. When you go up, the reaction of water and steam, reduction with carbon and acid increases.

Question 6

If 1 does not react with 2….

Answer 6

….than anything above 1 will react with 2

Question 7

reactivity of metals

Answer 7

the tendency of a metal atom to lose its electrons and become a positive ion

Question 8

Describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction in displacement reactions

Answer 8

In displacements reactions, they occur as one metal, higher in the reactivity series and therefore more reactive, displaces another metal. this can be in oxides, aqueous ions etc. example: aluminium + iron(III) oxide → iron + aluminium oxide

Question 9

heat and metal hydroxide

Answer 9

metal hydroxide —> metal oxide + steam (only zinc iron and copper decompose, the rest are too stable)

Question 10

heat and metal nitrate

Answer 10

metal nitrate —> metal oxide + nitrogen dioxide + oxygen (if metal is zinc, iron or copper)
metal nitrate —> metal nitrate + oxygen

Question 11

unreactive aluminium

Answer 11

Caused as the outer layer of aluminium reacts with oxygen to form aluminium oxide. This acts like a very unreactive layer of metal oxide which coats the aluminium

Question 12

Describe obtaining metals from their ores by relating the elements to the reactivity series

Answer 12

Metals are found as ores and are bound to other elements. To obtain pure metal, we must displace these other elements. For less reactive metals, this process is relatively simple. As zinc, iron and copper are less reactive than carbon, it is possible to obtain these metals in a pure state just by heating them strongly in the presence of carbon. For more reactive metals, electrolysis needs to take place.

Question 13

state the essential reactions in the extraction of iron from hematite

Answer 13

1. carbon + oxygen —> carbon dioxide
2. carbon dioxide + carbon —> carbon monoxide
3. iron oxide + carbon monoxide —> iron + carbon dioxide
4. iron oxide + carbon —> iron + carbon monoxide

Question 14

Describe the conversion of iron into steel using basic oxides and oxygen

Answer 14

Oxygen is blown into the molten iron. It reacts with the excess carbon to form CO_2 and CO which leave. It also reacts with the impurities in iron to form acidic oxides later removed with calcium oxide. The amount of oxygen blown into the molten iron is controlled to determine the final carbon content correct to produce steel.

Question 15

Describe the essential reactions in the extraction of iron from hematite

Answer 15

Iron ore, limestone and coke added to the blast furnace. Hot air moves to the top, formed from carbon combing with oxygen in an exothermic reaction. CO formed by reaction between oxygen and coke. CO and some carbon reduce iron oxide to iron by taking oxygen with them. Molten iron runs out from the bottom of the blast furnace

Question 16

Aluminium is extracted from the ore bauxite by….

Answer 16

…..electrolysis.

Question 17

advantages of recycling metals, limited to iron/steel and aluminium

Answer 17

• cheaper, as electrolysis is expensive af
• reduces environmental impact from mining and the extraction of new metals
• less waste produced so less landfill
• more sustainable - does not use up the finite resources
• less energy required compared to electrolysis

Question 18

disadvantages of recycling metals, limited to iron/steel and aluminium

Answer 18

• collection and transportation to recycling centres needed, therefore more air pollution
• sorting requires a lot of time and labour
• energy saving can not truly be determine as it varies between metals

Question 19

Describe in outline, the extraction of zinc from zinc blende

Answer 19

Zinc blende is heated to form zinc oxide, which is then reduced with carbon monoxide or its reduced with sulphuric acid and then electrolysed to produce pure zince

Question 20

Describe the extraction of aluminium from bauxite including the role of cryolite and the reactions at the electrodes

Answer 20

aluminium, due to its position in the reactivity series, needs to be electrolysed. However, it firstly needs to be dissolved in cryolite (as molten aluminium would be too impractical and expensive to electrolyse) beforehand. afterwards however, pure aluminium is formed at the cathode and oxygen at the anode.

Question 21

Name the uses of aluminium

Answer 21

the manufacture of aircraft because of its

strength and low density and food containers because of its resistance to corrosion

Question 22

Name the uses of copper

Answer 22

electrical wiring as it is a very good conductor and can bend easily and in cooking equipment because it is a good conductor of heat and therefore, can warm up food more quickly.

Question 23

Name the uses of mild steel

Answer 23

Car bodies and tough machinery as it is very tough, ductile, malleable and has a good tensile strength

Question 24

Name the uses of stainless steel

Answer 24

Cutlery and chemical plants as it is resistant to corrosion

Question 25

Explain the uses of zinc for galvanising and for making brass

Answer 25

Zinc is used for galvanising to coat steel to prevent rusting; as the zinc layer protects the steel by oxidising first. For making brass, zinc pairs with copper to increase the strength and hardness for brass.

Question 26

Describe the idea of changing the properties of iron by the controlled use of additives to form steel alloys

Answer 26

Different additives can be added to iron to make it in to different forms of steel. For example, the amount of carbon in the iron affects its hardness.