Metals

Question 1

Reaction with water: Mg Al Zn Fe

Answer 1

Very slow reaction with cold water. React when heated in steam producing an insoluble metal oxide and hydrogen

Question 2

Reaction with water: Cu Ag Au

Answer 2

No reaction with water or steam

Question 3

How do you find the reactivity of cobalt

Answer 3

Get 5 test tubes and add cobalt nitrate
Then add magnesium, zinc, silver, iron and copper
If the metal is more reactive than cobalt then the element will begin to form on the surface of the metal
If no reaction occurs the metal is less reactive

Question 4

What’s an ore

Answer 4

A mineral containing a metal compound from which the metal can be economically extracted

Question 5

What are the three stages involved in extracting metals

Answer 5

Mining the metal ore and concentrating it
Conversion of the metal ore into the metal
Purification of the metal

Question 6

What is aluminium extracted from

Answer 6

Bauxite (impure aluminium oxide)

Question 7

Give four metals that cannot be extracted from their ore by reduction with carbon or carbon monoxide

Answer 7

Potassium sodium lithium and magnesium

Question 8

How are potassium sodium lithium and magnesium extracted

Answer 8

By passing an electric current through a molten compound, which splits it up into the original elements (electrolysis)

Question 9

What is the main ore of iron

Answer 9

Haematite (iron (|||) oxide)

Question 10

How is iron extracted from its ore

Answer 10

The ore is grown up
It is mixed with limestone and coke
This is added to the top of the blast furnace
Air (preheated to 600 degrees Celsius) is injected into the furnace through pipes
Molten iron is tapped from the lower tap hole (slag is tapped from the higher one)
The process is continuous

Question 11

Name four substances (raw materials) that go into the blast furnace

Answer 11

Iron ore (Fe2O3)
Coke (treated coal)
Limestone (CaCO3)
Air (O2)

Question 12

Name three substances that come out of a blast furnace

Answer 12

Molten iron
Molten slag
Waste gases

Question 13

What happens at the bottom of a furnace

Answer 13

Coke reacts with oxygen in the hot air
C + O2 = CO2
This reaction is exothermic

Question 14

What does the heat produced during the reaction with coke and oxygen do

Answer 14

Decomposes limestone forming calcium oxide and more carbon dioxide
CaCO3 = CaO + CO2

Question 15

What happens when carbon dioxide works it’s way up the furnace

Answer 15

It is reduced to carbon monoxide at about 1500 degrees Celsius by reaction with more coke
CO2 + C = 2CO

Question 16

What is the main reducing agent in the blast furnace

Answer 16

Carbon monoxide, it reduces the haematite to iron at about 600 degrees Celsius and producing carbon dioxide

Fe2O3 + 3CO = 2Fe + 3CO2

Question 17

What is the main purpose of the limestone in a blast furnace

Answer 17

To remove impurities. These are mainly silica which, if left in the iron, would make it brittle and so they react and are neutralised at about 900 degrees Celsius by a basic oxide (formed by the thermal decomposition of limestone) to form slag
CaO + SiO2 = CaSiO3

Question 18

Why does the molten slag sit on top of the molten iron

Answer 18

It is less dense, and it is to prevent the reoxidation of the iron by preheated air

Question 19

Why is the iron from the blast furnace not very useful

Answer 19

It has a high concentration of carbon impurities and is very brittle

Question 20

Why is pure iron not useful

Answer 20

It is very soft and stretches easily and is less brittle than cast iron; it also rusts easily

Question 21

What is an alloy

Answer 21

A mixture of metals or of a metal and carbon

Question 22

What two substances are needed for iron to rust

Answer 22

Water and oxygen (iron (|||) oxide)

Question 23

Rust prevention methods

Answer 23

Paint (cars)
Grease (bicycle chains)
Plastic (chain link fence)

Question 24

What is sacrificial protection

Answer 24

When a block of metal more reactive than iron (eg zinc) is added to the iron. So it will corrode before the iron does

Question 25

What is galvanising

Answer 25

When iron is protected from rusting by dipping the iron into molten zinc so that the iron is completely coated. It is used for dustbins and buckets

Question 26

Where are transition metals in the periodic table

Answer 26

The central block

Question 27

Mild steel

Answer 27

Malleable

Used in car bodies chains and pylons

Question 28

Hard steel

Answer 28

Hard and strong

Used in chisels files saws and razor blades

Question 29

Stainless steel

Answer 29

Does not rust

Used in cutlery kitchen sinks sculptures and surgical instruments

Question 30

Titanium steel

Answer 30

Low density high strength does not rust

Used in the edges of high speed cutting tools, armour plating, darts viola strings and golf clubs

Question 31

Equation for the reaction at the cathode

Answer 31

3+ _

Al + 3e = Al

Question 32

Equation for reaction at anode

Answer 32

2- + -

2O = O2 + 4e

Question 33

What are the anode and cathode made of

Answer 33

Graphite

Question 34

Where is the cathode in an electrolytic cell

Answer 34

At the bottom, below the molten aluminium

Question 35

Why does the anode need frequent replacement

Answer 35

At 1000 degrees Celsius the graphite anodes burn away in the oxygen to give carbon dioxide

Question 36

Why is cryolite added in the electrolyte

Answer 36

To reduce the operating temperature of aluminium from 2000-800 degrees Celsius and when it is molten it acts as a solvent for the alumina

Question 37

What kind of melting points and boiling points do metals have

Answer 37

High

Question 38

What kind of melting and boiling points to non metal as have

Answer 38

Low unless they have a giant covalent lattice structure

Question 39

reaction with water: K Na Li Ca

Answer 39

React with cold water giving soluble metal hydroxide and hydrogen