2(d, e)

Question 1

What is an alloy?

Answer 1

Metallic substance of a metal and other elements. Alloys are not chemically bonded therefore they are not defined as a compound.

Question 2

Why are alloys harder or stronger than metals?(3)

Answer 2

Alloys contain atoms of different sizes. These different sizes distort the regular arrangements of atoms. This makes it more difficult for the layers to slide over each other, so alloys are harder than the pure metal.

Question 3

Describe electrolysis in covalent compounds?(2)

Answer 3

Other than H2O, covalent compounds cannot be electrolysed.
This is because in order for a current to flow there must be charged particles that are free to move.

Question 4

Describe electrolysis in ionic compounds?(2)

Answer 4

Ionic compounds can be electrolysed.
These compounds can be electrolysed in a solution because if it is molten it will conduct electricity.

Question 5

How do metals conduct electricity?(2)

Answer 5

Metals conduct electricity because the delocalised electrons are free to move throughout the structure. The sea of delocalised electrons is from the outer shell of each atom.

Question 6

How are metals malleable?(2)

Answer 6

When we apply a force to a piece of metal the layers of the positive ions slide over each other. This does not affect the bonding in the structure. This explanation is the same reason for why metals are ductile.

Question 7

State the reaction between Magnesium and Copper oxide.(3)

Answer 7

Mg + CuO => MgO + Cu
Black and grey mixture of copper oxide and magnesium powder at the start.
Traces of white magnesium oxide left on at the end.

Question 8

State the reaction between Carbon and Copper oxide.(3)

Answer 8

C + 2 CuO => CO2 + 2Cu
Black mixture of carbon and copper oxide heated at the start.
Pink-brown copper left at the end.

Question 9

State the reaction between Zinc and Copper Sulphate solution.(2)

Answer 9

Zn + CuSO4 => ZnSO4 + Cu
Blue colour of copper sulphate solution fades as colourless zinc sulphate solution is formed.

Question 10

State the reaction between Copper and Silver Nitrate solution.(2)

Answer 10

Cu +2AgNO3 =>Cu(NO3)2 + 2Ag
The silver being produced looks like a mixture of grey ‘fur’ and delicate crystals.

Question 11

State the reaction of Calcium with cold water.(2)

Answer 11

Ca + 2H2O => Ca(OH)2 + H2
Exothermic, calcium reacts gently.

Question 12

State the reaction of Magnesium with cold water.(2)

Answer 12

No reaction.
Magnesium becomes coated with insoluble magnesium hydroxide which prevents water coming into contact.

Question 13

Sate the reaction of Iron with steam.(2)

Answer 13

3Fe + 4H2O => Fe3O4 + 4H2
Iron becomes slightly darker grey. Tri-iron tetroxide formed.

Question 14

State the reaction of magnesium with steam.(2)

Answer 14

Mg + H2O => MgO + H2.
Magnesium burns with bright white flame and produces hydrogen.

Question 15

What is required for iron to rust?(2)

Answer 15

Iron rusts in the presence of oxygen and water. Rusting is described as a redox reaction where iron is oxidised.

Question 16

How can rusting be prevented through barriers?(3)

Answer 16

By coating the iron in oil or grease or covering in plasticity will keep the water and oxygen away from it.
It is cheap but once the coating is broken, the iron will rust.

Question 17

How can rusting be prevented through galvanising?(3)

Answer 17

Galvanised iron is iron that is coated with zinc.
Even when some of the zinc coating is scratched away, the iron still won’t rust. This is because the zinc is more reactive and therefore will oxidise instead of the iron.

Question 18

How can rusting be prevented through sacrificial protection?(3)

Answer 18

Zinc, magnesium or aluminium blocks are attached to metal hulls of ships to prevent the iron rusting. This is similar but not the same as galvanising because galvanising is combination of barrier and sacrificial methods.

Question 19

Define a mineral?

Answer 19

A mineral is a metal combined with other elements in a chemical compound.

Question 20

How are metals extracted from minerals if they are less reactive than Carbon?(3)

Answer 20

The cheapest method for these metals is heating it with carbon. Carbon is higher in the reactivity series and will take the oxygen or element away from the metal and leave the metal as pure. Iron for example is extracted in this way in a blast furnace.

Question 21

How are metals extracted from minerals if they are more reactive than Carbon?(3)

Answer 21

Metals more reactive are usually extracted by electrolysis. The Cathode reduces and the Anode oxidises substances. Therefore the Anode is positively charged and the Cathode is negatively charged. Electrolysis is very expensive because it requires lots of electricity.

Question 22

State the uses of Aluminium, copper and iron.(3)

Answer 22

Electricity cables, water pipes, and bridges respectively.

Question 23

State the uses of Mild, High-Carbon and Stainless Steel.(3)

Answer 23

Car bodies, Cutting tools and Saucepans respectively.

Question 24

What are the inputs and outputs of a blast furnace?(3)

Answer 24

Coke(C), Iron ore(Fe2O3), limestone(CaCO3) are put into the furnace.
Molten iron and slag are outputted.
Hot air is also put into the blast furnace.

Question 25

What are the important reactions that take place in a blast furnace?(4)

Answer 25

C + O2 » CO2, very exothermic, heat energy produced is used.
CO2 + C » 2CO, carbon monoxide is required as a reducing agent.
Fe2O3 + 3CO » 2Fe + 3CO2, required to produce molten iron.
CaO + SiO » CaSiO3, neutralisation reaction.