Metals

Question 1

what is metallic bonding?

Answer 1

A metallic bond is the attraction between the positive metal ions and delocalised electrons

Question 2

State the 3 physical properties of pure metals

Answer 2

• Good conductors of electricity and heat
• Usually have high densities, m.p b.p
• Malleable and ductile

Question 3

Explain why metals are good conductors of electricity and heat

Answer 3

Beacuse the delocalized electrons are able to move freely within the metal lattice and act as mobile charge carriers.

Question 4

Explain why metals have high desnsities, mp and bp

Answer 4

Atoms of a metal are held together by strong forces of attractions(metallic bonds). A large amount of energy is required to break these strong metallic bonds

Question 5

Explain why

Answer 5

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Question 6

Explain why metals are malleable and ductile

Answer 6

As the same sized metal atoms are regularly arranged in layers. When a force is applied, The layers of metal atoms are able to slide over one another easily.
Metals can thus be hammered into different shapes (malleable)
Metals can also be drawn into wires without breaking (ductile)

Question 7

Why are pure metals not often used in the industry?

Answer 7

pure metals
- are soft
atoms are packed regularly in layers and when a force is applied, the layers of atoms can slide over one another easily.
- may react with air and water and wear away or corrode easily
thus the industry often use alloys

Question 8

what is an alloy?

Answer 8

an alloy is a mixture of a metal and one or a few other elements.

Question 9

what is an alloy?k

Answer 9

- to improve the appearance of metals:
pewter
- to lower the mp. and b.p of metals:
 solder
- more resistant to corrosion :
 coins , cupronickel - copper + nickel
- make metals harder and stronger:
trumpets, brass - copper + zinc

Question 10

what is brass composition

Answer 10

brass = copper + tin

Question 11

what is steel composition

Answer 11

iron + carbon

Question 12

explain the structure of an alloy and how it affects the malleability.

Answer 12

In an alloy, the atoms of different elements are different sizes, which disrupts the regular structure. Thus, when a force is applied, the atoms cant slide over one another easily. This is why alloys are stronger and harder than pure metals.

Question 13

State the Reactivity series

Answer 13

Potassium
Sodium
Calcium
Magnesium 
Aluminium
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold 
Platinum

Question 14

state the metals that will react with steam only and not with cold water

Answer 14

Reactivity Series:
Potassium
Sodium
Calcium
Magnesium 
Aluminium
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold 
Platinum
Below aluminium but above lead.
Zinc, Iron, Tin

Question 15

state the metals that does not react with acid?

Answer 15

Reactivity Series:
Potassium
Sodium
Calcium
Magnesium 
Aluminium
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold 
Platinum
Metals that are below hydrogen in the reactivity series do not react with acid
Copper, Silver, Gold and Platinum

Question 16

state the metals that will react with both water and steam

Answer 16

Reactivity Series:
Potassium
Sodium
Calcium
Magnesium 
Aluminium
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold 
Platinum

The first four metals in the reactivity series can react with both steam and water. Potassium, Sodium, Calcium and Magnesium.

Question 17

State the metals that will form coloured salts

Answer 17

Transition metals in-between group 2 and 3 are coloured salts. Like Iron, Copper and Gold

Question 18

Which metal reacts slowly with cold water?

Answer 18

First four metals of the reactivity series react with cold water. Potassium, Sodium, Calcium, Magnesium
Potassium- Very violently
Magnesium- Slowly
Therefore magnesium reacts slowly with cold water

Question 19

What happens when a reactive metal reacts with (cold) water?

Answer 19

Metal Hydroxide and Hydrogen gas is formed.

metal + water H20 - metal hydroxide + hydrogen gas H2

Question 20

What happens when a reactive metal reacts with steam?

Answer 20

Metal Oxide and Hydrogen gas is formed.

metal + water H20 - metal oxide + hydrogen gas H2

Question 21

Why can’t lead(II) chloride react with hydrochloric acid?

Answer 21

Because the surface of lead will react with hydrochloric acid and form an insoluble layer of lead (II) chloride that prevents the pure lead from reacting.

Question 22

What is the name of the gas produced and how to identify it when reactive metals react with water?

Answer 22

metal + water H20 - metal hydroxide + hydrogen gas H2

Hydrogen gas: Insert a lighted splint into the gas and it should extinguish with a pop sound.

Question 23

State the metals that does not react with both water and steam

Answer 23

Lead and below.

Lead, (Hydrogen), Copper, Silver, Gold, Platinum

Question 24

Why cant aluminium react with water?

Answer 24

The aluminium metal surface reacts with oxygen in the air to form aluminium oxide, preventing any reaction with water

Question 25

what happen when a reactive metal react with acid?

Answer 25

metal + acid - salt + hydrogen gas

Question 26

What are the 3 materials being added to the top of the blast furnace?

Answer 26

3 Raw materials added:

• Haematite (iron ore)
• Coke (mainly carbon)
• Limestone (calcium carbonate)

Question 27

What is the purpose of limestone?

Answer 27

Limestone is also known as calcium carbonate is to remove impurities like sand, etc.

Question 28

What is haematite?

Answer 28

Iron ore. Haematite contains iron(III) sulfate mixed with impurities such as sand and clay

Question 29

what chemical reaction takes place in the blast furnace?

Answer 29

In a blast furnace, a series of chemical reaction takes place.

Question 30

steps for the extraction of iron

Answer 30

1. the carbon in coke burns in a blast of hot air, producing carbon dioxide, this reaction produces alot of heat
2. the carbon dioxide rises up the furnace and reacts with more coke (carbon) to form carbon monoxide
3. the carbon monoxide reduces the iron(III)oxide in haematite to iron.
4. limestone (calcium carbonate) is decomposed by heat to produce carbon dioxide and calcium oxide.
   as calcium oxide is a basic, it reats with silicon dioxide which is acidic, and other impurities in haematite, forming molten slag (calcium silicate)
   hot waste gases (carbon monoxide, carbon dioxide, nitrogen) escape throught the top of the furnace.
   the molten slag runs down to the bottom of the furnace and floats ontop if molten iron as slag has a lower density than molten iron

Question 31

steps for the extraction of iron

Answer 31

1. the carbon in coke burns in a blast of hot air, producing carbon dioxide, this reaction produces alot of heat
2. the carbon dioxide rises up the furnace and reacts with more coke (carbon) to form carbon monoxide
3. the carbon monoxide reduces the iron(III)oxide in haematite to iron.
4. limestone (calcium carbonate) is decomposed by heat to produce carbon dioxide and calcium oxide.
   as calcium oxide is a basic, it reats with silicon dioxide which is acidic, and other impurities in haematite, forming molten slag (calcium silicate)
   hot waste gases (carbon monoxide, carbon dioxide, nitrogen) escape throught the top of the furnace.
   the molten slag runs down to the bottom of the furnace and floats ontop if molten iron as slag has a lower density than molten iron

Question 32

what are the waste gases coming out from the blast furnace?

Answer 32

carbon monoxide CO, carbon dioxide CO2 and nitrogen N2

Question 33

why does molten slag floats on top molten iron in the blast furnace?

Answer 33

slag has a lower density than molten iron thats why it floats ontop of iron.

Question 34

what can slag be used for?

Answer 34

slag can be used for resurfacing roads.

Question 35

why is molten iron below molten slag in the blast furnace?

Answer 35

molten iron has a higher density than molten slag causing it to sink to the bottom of the furnace and slag floats on top of it.