Extraction and uses of metals

Question 1

Explain, with reference to the structure, why neodymium is malleable and a good conductor of electricity.

Answer 1

• Neodymium ions are packed in layers
• Those ions can slide past each other
• They contain delocalized electrons
• These delocalized electrons can freely move

Question 2

What does the reaction suggest about the reactivity of aluminum compared to the reactivity of iron? Explain your answer.

Answer 2

• Aluminium is more reactive than iron
• Aluminium displaces iron

Question 3

What is meant by the term catalyst?

Answer 3

A substance that increases the rate of reaction

Question 4

Explain why molybdenum is malleable

Answer 4

• Molybdenum ions are in layers
• positive ions slide over each other

Question 5

Name the main ore used as the source of iron

Answer 5

Haematite

Question 6

Identify the element and state its purpose in the extraction of aluminum

Answer 6

Element: Carbon
Purpose: Positive electrode

Question 7

Identify the element and state its purpose in the extraction of iron

Answer 7

Element: Oxygen
Purpose: Production of heat

Question 8

State one reason why cryolite is used in the extraction of aluminium

Answer 8

• To lower the temperature

Question 9

Name two substances that must be present for iron to rust

Answer 9

• Water
• Oxygen

Question 10

How does the method of painting prevent rusting to occur?

Answer 10

Prevents water from coming in contact with iron

Question 11

Explain how this method of protection works, even when the surface of the zinc is scratched to expose the iron underneath.

Answer 11

• Zinc is more reactive than iron and therefore, corrodes in preference to iron

Question 12

Why is aluminum not extracted by heating its oxide with carbon monoxide?

Answer 12

Aluminium is more reactive than carbon

Question 13

Why is iron not extracted from its oxide using electrolysis?

Answer 13

Electricity is expensive

Question 14

Suggest why distillation can be used to remove magnesium chloride from titanium

Answer 14

Magnesium chloride has lower b.pt

Question 15

State two other methods used to prevent iron from rusting

Answer 15

• Painting
• Oiling/greasing

Question 16

Name the main compound present in limestone

Answer 16

Calcium Carbonate

Question 17

Why would lead not be suitable for use in the electrical circuits of a probe to land on Venus?

Answer 17

It has a low melting point

Question 18

Why do metals higher in the reactivity series require electrolysis for extraction?

Answer 18

Metals higher in the reactivity series, such as those above carbon, are too reactive to be reduced by carbon. Therefore, electrolysis is needed for their extraction.

Question 19

Provide an example of an alloy and its composition.

Answer 19

Brass, an alloy containing 70% copper and 30% zinc.

Question 20

Explain why alloys are harder than pure metals.

Answer 20

Alloys have atoms of different sizes, disrupting regular arrangements and making it harder for layers to slide over each other

Question 21

Describe the properties of mild steel and its use.

Answer 21

0.25% carbon, is soft and malleable, used in car body panels and wires.

Question 22

Why is copper used in electrical wires?

Answer 22

Copper is a good conductor of electricity and malleable

Question 23

Name a significant property of aluminum and its use in aeroplane bodies.

Answer 23

High strength-to-weight ratio (low density)

Question 24

What is bacterial extraction in metal extraction processes?

Answer 24

Bacterial extraction occurs when bacteria absorb metal compounds, producing leachates containing the metals

Question 25

Explain phytoextraction in metal extraction processes.

Answer 25

Phytoextraction involves:

• plants absorbing metal compounds through their roots
• concentrating them
• producing ash containing the metal when burned.

Question 26

In metal extraction, how does the reactivity series influence the method of extraction?

Answer 26

The method of extraction is determined by the metal’s position in the reactivity series.

• Higher-placed metals require electrolysis
• Lower-placed metals can be extracted by heating with carbon.

Question 27

Why do unreactive metals like gold and platinum not require chemical extraction?

Answer 27

Unreactive metals are often found as the uncombined element

Question 28

What is the definition of an ore?

Answer 28

An ore is a rock that contains enough of a metal to make it worthwhile extracting.

Question 29

Why is magnalium harder than aluminum?

Answer 29

• Magnalium is an alloy, whereas aluminum is a metal
• Magnalium being the alloy is harder because the atoms of the mixed metals are different sized, disrupting the regular arrangement and making it harder for layers to slide over each other.

Question 30

What is meant by the term alloy?

Answer 30

homogeneous mixture of two or more metals, or a metal and a non metal