Topic 4 - Extracting Metals and Equilibria

Write the metals reactivity series from most to least reactive.

Potassium (K), Sodium (Na), Lithium (Li), Calcium (Ca), Magnesium (Mg), Aluminium (Al), Carbon (C), Zinc (Zn), Iron (Fe), Hydrogen (H), Copper (Cu), Silver (Ag), Gold (Au).

Are more reactive metals more or less resistant to corrosion?

Less.

Are less reactive metals more or less resistant to corrosion?

More.

P, R, Q and S.

What is the reaction between a metal and water?

Metal + Water = Metal Hydroxide + Hydrogen.

What is the reaction between a metal and water?

Metal + Water = Salt + Hydrogen.

What are the products when a metal reacts with water?

Metal hydroxide and hydrogen gas.

What is the reaction between a metal and acid?

Metal + Acid = Salt + Hydrogen.

What are the products when a metal reacts with acid?

Salt and hydrogen.

If a metal reacts with cold water, what does it suggest about the reactivity of the metal?

Metal is very reactive as only the most reactive metals can react with water.

A metal reacts with oxygen but not water or acid. What does this suggest about the metals reactivity?

Not very reactive as most metals react with oxygen but only the most reactive react with water/acid.

What do only metals above hydrogen in the reactivity series react with?

Acid.

Name a metal which will not react with water, acid or oxygen.

Gold.

Why does gold not react with acid, water or oxygen?

It is extremely unreactive.

If a metal reacts with water, what does this suggest about this reactivity?

Very reactive.

If a metal reacts with acid, what does this suggest about this reactivity?

Quite reactive.

What is a displacement reaction?

When a more reactive elements reacts with a less reactive one in a compound.

What would you expect to observe when magnesium is added to copper sulfate solution?

• Copper sulfate solution is blue.

• Magnesium is more reactive than copper so when added, blue solution decolourises.

In a displacement reaction, which element is oxidised and loses electrons?

More reactive.

In a displacement reaction, which element is reduced and gains electrons?

Less reactive.

Why can a displacement reaction be called a REDOX reaction?

• A redox reaction is when reduction and oxidation are taking place at the same time.

• In a displacement reaction, the more reactive metal atoms lose electrons to form ions. This is oxidation.

• In a displacement reaction, the less reactive metal atoms gains electrons to form the element. This is reduction.

The reactivity of a metal is related to its tendency to form ___

Cations.

A metal easily loses electrons to form cations. What does those suggest about its reactivity?

Very reactive.

A metal struggles to lose electrons to form cations. What does those suggest about its reactivity?

Unreactive.

A metal is easily oxidised. What does those suggest about its reactivity?

Very reactive.

A metal is resistant to oxidation. What does those suggest about its reactivity?

Unreactive.

Why do elements high up in the reactivity series form cations easily?

They are more likely to react with water and acid.

How is a metals relative resistance to oxidation related to its position in the reactivity series?

• Oxidation is the loss of electrons.

• Metals that are lower in the reactivity are less reactive which means they are less likely to form cations so more resistant to oxidation.

• Metals that are higher in the reactivity are more reactive which means they are more likely to form cations so less resistant to oxidation.

Where are most metals extracted from?

From ores found in the Earth’s crust.

What are metal ores?

Rocks that contain enough of the metal to make it worthwhile extracting the metal.

Which metals are found in the earth’s crust as uncombined elements?

Unreactive metals.

Which metals are found in the earth’s crust as combined elements?

Reactive metals.

Some ores contain metals chemically combined with oxygen. What process must be carried out to extract the metal?

Reduction using carbon.

How are metals that are less reactive than Carbon extracted from their ores?

Reduction using carbon.

How are metals that are more reactive than Carbon extracted from their ores?

Electrolysis.

How would you extract iron from its ore?

Iron is less reactive than carbon so can be extracted by reduction with carbon.

Explain the process of extracting a metal less reactive than carbon from its ore.

• Carried out in a blast surface.

• Metal is reduced and loses oxygen but gains electrons.

• Carbon is oxidised and gains oxygen but loses electrons.

How would you extract aliminium from its ore?

Aliminium is more reactive than carbon so electrolysis is used.

Explain the process of extracting a metal less reactive than carbon from its ore.

• Metal is manufactured by the electrolysis of a melted compound.

• Metal is discharged at the cathode and non metal at the anode.

How can aliminium be extracted from its ore?

• Aliminium is more reactive than carbon so electrolysis must be used.

• Molten ore undergoes electrolysis.

• Metal is discharged at the cathode and non metal at the anode.

How are metals that are higher than carbon in the reactivity series extracted?

Electrolysis.

Predict the method that will have to be used to extract calcium from its ore.

Electrolysis.

Pick A, B, C or D.

C.

Which metals can be found as pure/native metals? Why?

Platinum, gold and silver because they are unreactive.

What are low grade ores?

Ores that only contain small amounts of metal.

How can plants be used as an alternative metal extraction method?

• Phytoextraction.

• Plants are grown in areas with metals in the soil.

• The plants take up metals through their roots and concentrate them in their shoots and leaves.

• These plants are harvested, dried and burned and the metals are removed through ash.

• The ash contains metal compounds that can be extracted in electrolysis or displacement reactions.

Describe how growing plants can result in the phytoextraction of copper.

• Plants absorb copper ions from the soil to their leaves/shoots.

• These parts of the plant can then be dried, burned and harvested in a furnace and removed through ash.

• The ash contains metal compounds that can be extracted in electrolysis or displacement reactions.

What are the advantages of recycling metals?

• Economically beneficial because recycling metals is cheaper than extraction methods like electrolysis which is expensive.

• Prevents environmental damage of mining and extraction of new metals, which are damaging to the environment and ecosystems.

• Less waste produced so less landfill sites which take up space and pollute the surroundings.

• More sustainable by not using up finite resources.

• Recycling process provides employment.

What are the disadvantages of recycling metals?

• Materials must be sorted beforehand which requires energy and labour.

• May not be the same quality as the original.

• Workers and vehicles need to be organised and maintained.

What is a life cycle assessment?

Analysis of the overall environmental impact that a product may have throughout its lifetime.

What different factors does a life cycle assessment of a product consider?

• Extraction and processing of raw materials.

• Manufacturing.

• Usage of product.

• Disposal.

What may be evaluated in extraction and processing of raw materials during life assessments?

• Metals must be mined and extracted from their ores which requires energy and can cause pollution.

• Raw materials often come from crude oil, a non renewable resource, and supplies are limited.

• Obtaining crude oil requires energy and may cause pollution.

• Mining damages habitats and may lead to deforestation in order to clear space.

What may be evaluated in the manufacture during life assessments?

• May cause pollution and uses lots of energy.

• Disposal of waste products could be dangerous but others may be able to be recycled for use.

• Factories may lead to land being cleared, damaging habitats.

• Process may require water. This polluted water must be disposed of carefully and cannot be put back into the environment.

• Use of fossil fuels for machinery and transport damages the environment.

What may be evaluated in the usage during life assessments?

• Paint gives off toxic fumes.

• Burning fuels releases greenhouse gases.

• Fertilisers may leach into streams to damage ecosystems.

What may be evaluated in the disposal during life assessments?

• Uses up space at landfill sites, which can pollute the Earth.

• Products may be incinerated (burnt), causing air pollution.