Extracting Metals and Equlibria

Question 1

What do more reactive metals do in chemical reactions?

Answer 1

Lose electrons to become cations

Question 2

What is the relationship between metal reactivity and cation formation?

Answer 2

The more reactive the metal, the more easily it becomes a cation

Question 3

What is the general reaction for a metal becoming a cation?

Answer 3

M ⟶ Mn+ + ne-

Question 4

What process is described by the loss of electrons?

Answer 4

Oxidation

Question 5

How does the position of a metal in the reactivity series affect oxidation?

Answer 5

The higher up the metal is in the reactivity series, the more easily it will undergo oxidation

Question 6

What can be said about unreactive metals in terms of oxidation?

Answer 6

They are more resistant to oxidation

Question 7

What does the Earth’s crust contain?

Answer 7

Metals and metal compounds such as gold, copper, iron oxide, and aluminium oxide

These elements are fundamental in various industrial and technological applications.

Question 8

What are useful metals often combined with?

Answer 8

Other substances forming ores

This combination is essential for the extraction process.

Question 9

What is a metal ore?

Answer 9

A rock that contains enough of the metal to make it worthwhile extracting

The economic viability of extracting a metal is determined by the concentration of the metal in the ore.

Question 10

How must metals be extracted from their ores?

Answer 10

Through processes such as electrolysis, using a blast furnace, or by reacting with more reactive material

These methods depend on the type of metal and its ore.

Question 11

What type of process is often involved in the extraction of metal oxides?

Answer 11

A reduction process since oxygen is being removed

This is crucial for metals that are found in oxide form.

Question 12

What are common examples of oxide ores?

Answer 12

• Haematite (iron ore)
• Bauxite (aluminium ore)

These ores are significant sources of their respective metals.

Question 13

What are unreactive metals?

Answer 13

Metals that do not have to be extracted chemically as they are often found as the uncombined element

Their stability allows them to exist in nature in a free state.

Question 14

What are native metals?

Answer 14

Unreactive metals that do not easily react with other substances due to their chemical stability

This characteristic allows them to be found in their elemental form.

Question 15

Give two examples of native metals.

Answer 15

• Gold
• Platinum

Both metals can be mined directly from the Earth’s crust.

Question 16

What is the tendency to become oxidised linked to?

Answer 16

How reactive a metal is and its position on the reactivity series

Metals higher up in the reactivity series are more prone to oxidation.

Question 17

How do metals higher up in the reactivity series compare to those lower down regarding oxidation?

Answer 17

Metals higher up are less resistant to oxidation than metals lower down

This means they oxidize more easily.

Question 18

What determines the method of extraction for metals?

Answer 18

The position of the metal on the reactivity series

This influences whether electrolysis or reduction by carbon is used.

Question 19

What extraction method is used for higher placed metals (above carbon)?

Answer 19

Electrolysis

These metals are too reactive to be reduced by carbon.

Question 20

How can lower placed metals be extracted?

Answer 20

By heating with carbon

This method reduces the metals.

Question 21

What is phytomining?

Answer 21

A process that takes advantage of how some plants absorb metals through their roots

Phytomining is used to extract metals from soil by utilizing plant biology.

Question 22

Where are plants grown for phytomining?

Answer 22

In areas known to contain metals of interest in the soil

This location is crucial for ensuring the plants can absorb the desired metals.

Question 23

How do plants absorb metals in phytomining?

Answer 23

Through their roots and into their vascular system

This biological process allows for the concentration of metals in specific plant parts.

Question 24

Which parts of the plant are harvested in phytomining?

Answer 24

Shoots and leaves

These parts contain concentrated metal compounds that are useful for extraction.

Question 25

What happens to the harvested plant parts in phytomining?

Answer 25

They are dried and burned ## Footnote This process converts the biomass into ash that contains metal compounds.

Question 26

What is extracted from the ash produced in phytomining?

Answer 26

Metal compounds ## Footnote These compounds can be processed to recover useful metals.

Question 27

What methods can be used to extract metals from the ash in phytomining?

Answer 27

Displacement reactions or electrolysis ## Footnote These methods are effective for recovering metals from the ash.

Question 28

What is bioleaching?

Answer 28

Bioleaching is a technique that makes use of bacteria to extract metals from metal ores ## Footnote Bioleaching leverages biological processes for metal extraction.

Question 29

Which type of bacteria is used in bioleaching?

Answer 29

Some strains of bacteria are capable of breaking down ores to form acidic solutions containing metal ions such as copper(II) ## Footnote These bacteria facilitate the leaching process.

Question 30

What is the solution called that contains metal ions in bioleaching?

Answer 30

The solution is called a leachate which contains significant quantities of metal ions ## Footnote Leachate is crucial for the extraction process.

Question 31

How can metal ions in leachate be extracted?

Answer 31

Metal ions can be reduced to the solid metal form and extracted by displacement reactions or electrolysis ## Footnote These methods enable the recovery of metals from leachate.

Question 32

What types of ores are often used in bioleaching?

Answer 32

Bioleaching is often used to extract metals from sulfides e.g. CuS or Fe2S ## Footnote Sulfide ores are a common target for bioleaching processes.

Question 33

Does bioleaching require high temperatures?

Answer 33

No, bioleaching does not require high temperatures ## Footnote This makes bioleaching an energy-efficient method of metal extraction.

Question 34

What environmental concern is associated with bioleaching?

Answer 34

Bioleaching produces toxic substances which need to be treated so they don’t contaminate the environment ## Footnote Managing toxic byproducts is essential for environmental protection.

Question 35

In addition to primary extraction, what is another use of bioleaching?

Answer 35

Bioleaching is also used in mining waste clean up operations ## Footnote This application helps mitigate the impact of mining activities.

Question 36

What process is used to manufacture ammonia?

Answer 36

The Haber Process ## Footnote The Haber Process is a method for synthesizing ammonia from nitrogen and hydrogen gases.

Question 37

What is the first stage of the Haber Process?

Answer 37

H2 and N2 are obtained from natural gas and the air respectively and are pumped into the compressor through pipe ## Footnote Hydrogen (H2) is sourced from natural gas, while nitrogen (N2) is sourced from the air.

Question 38

What happens in the second stage of the Haber Process?

Answer 38

The gases are compressed to about 200 atmospheres inside the compressor ## Footnote High pressure is essential for the reaction to form ammonia.

Question 39

What temperature is maintained in the third stage of the Haber Process?

Answer 39

450°C ## Footnote This temperature is optimal for the catalytic reaction to occur.

Question 40

What is the chemical equation for the formation of ammonia in the Haber Process?

Answer 40

N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ## Footnote This equation represents the reversible reaction between nitrogen and hydrogen to form ammonia.

Question 41

What occurs in the fourth stage of the Haber Process?

Answer 41

Unreacted H2 and N2 and product ammonia pass into a cooling tank where ammonia is liquefied and removed ## Footnote This stage involves cooling to facilitate the liquefaction of ammonia.

Question 42

What happens to unreacted gases in the fifth stage of the Haber Process?

Answer 42

The unreacted H2 and N2 gases are recycled back into the system ## Footnote Recycling unreacted gases increases efficiency and sustainability of the process.

Question 43

What is one environmental impact of obtaining raw materials?

Answer 43

Using up limited resources such as ores and crude oil ## Footnote This can lead to resource depletion.

Question 44

How can obtaining raw materials damage habitats?

Answer 44

Through deforestation or mining ## Footnote This results in loss of biodiversity and ecosystem disruption.

Question 45

What is one impact of manufacturing processes on the environment?

Answer 45

Using up land for factories ## Footnote This can lead to habitat loss and urban sprawl.

Question 46

What type of machines contribute to environmental impact during production?

Answer 46

Fossil fuelled machines for production and transport ## Footnote These machines emit greenhouse gases and contribute to air pollution.

Question 47

How does the usage of a product affect the environment?

Answer 47

It depends on the type of product ## Footnote For example, a wooden desk has very little impact, while a car has a significant impact.

Question 48

What is one environmental concern regarding the disposal of outdated products?

Answer 48

Using up space at landfill sites ## Footnote This can lead to land degradation and pollution.

Question 49

What factor affects whether a product or its parts can be recycled?

Answer 49

The type of product ## Footnote Some materials are more easily recyclable than others.

Question 50

What is a life cycle assessment?

Answer 50

An assessment carried out using the data of a given product and the criteria of the assessment ## Footnote It evaluates the environmental impacts associated with all stages of a product's life.

Question 51

Is there a perfect product with zero environmental impact?

Answer 51

Rarely ## Footnote Most products involve a compromise between environmental impact and economical factors.

Question 52

Disadvantages of recycling

Answer 52

Disadvantages Collection and transport of material to be recycled requires energy and fuel Workers, vehicles and worksites need to be organised and maintained Materials need to be sorted before they can be recycled which also requires energy and labour Products made from recycled materials may not always be of the same quality as the original