Obtaining & Using Metals (Edexcel GCSE Combined Science: Chemistry): Flashcards

Metals that are more reactive than hydrogen in the reactivity series will react with dilute acids to produce a salt and hydrogen gas.

True.

Potassium reacts violently with water and acid.

Displacement occurs when a more reactive substance takes the place of a less reactive substance.

False.

Reactivity is determined by the tendency of the metal atoms to lose electrons.

Observations made when copper sulfate solution reacts with magnesium:

• The blue colour of the solution fades

• Copper forms at the bottom of the beaker

True.

Magnesium can displace copper from copper sulfate solution.

Oxidation is the loss of electrons.

The balanced symbol equation is:

Zn (s) + CuSO₄ (aq) → ZnSO₄ (aq) + Cu (s)

In a metal displacement reaction, the more reactive metal is oxidised and the less reactive metal ion is reduced.

Reduction is the gain of electrons.

A redox reaction is one where oxidation and reduction occur simultaneously.

True.

In the reaction, magnesium has been oxidised as it has lost electrons.

The species which has been reduced is copper as it has gained electrons.

Higher Tier only

The half equation for the oxidation of zinc atoms is:

Zn ⟶ Zn²⁺ + 2e^-

Higher Tier only

A half equation for the reduction of copper ions is:

Cu²⁺ + 2e^- ⟶ Cu

The reactivity series orders metals from most reactive to least reactive.

Metals that are above carbon in the reactivity series cannot be extracted by reduction with carbon and must instead be extracted by electrolysis.

Metals above carbon in the reactivity series are extracted by electrolysis.

False.

The most reactive metals are at the top of the reactivity series.

The position of the metal on the reactivity series determines the extraction method.

Metals that must be extracted by electrolysis are higher up the reactivity series (above carbon) and include aluminium, sodium, potassium, calcium, lithium and magnesium.

False.

Iron is extracted by reduction with carbon / in the blast furnace.

Metals below carbon in the reactivity series are extracted by reduction with carbon.

False.

Metals higher up are less resistant to oxidation than the metals placed lower down, which are more resistant to oxidation.

When extracted by heating with carbon, the metal undergoes a reduction reaction.

A low grade ore is an ore with a lower quantity of metal than a high grade ore.

Bioleaching is a technique that uses bacteria to extract metal ions from low-grade ores by producing an acidic leachate solution containing the metal.

Bioleaching produces toxic substances that need to be treated to avoid environmental contamination.

A leachate is an acidic solution containing significant quantities of metal ions.

True.

Bioleaching is often used to extract metals from sulfides (e.g. CuS or Fe₂S).

Phytomining is a process that uses plants to absorb metals from the soil.

The four stages of phytomining are:

1. The plants are grown in areas known to contain metals

2. Plants take up metals as they grow

3. The plants are harvested, dried and burned

4. Displacement or electrolysis is used to extract the metals from the ash

The plants are harvested, dried, and burned. The metal compounds in the ash are then extracted by displacement or electrolysis.

In phytomining, plants absorb metal compounds from the soil as they grow, and the metal is then recovered from the plant ash after harvesting and burning.

Copper and nickel have ores that are becoming less available.

Two advantages of using bioleaching and phytomining to extract metals from ores are:

• Can be used to extract metals from low grade ores

• Avoid the significant environmental damage caused by traditional mining methods

Recycling metals provides employment and is economically beneficial, especially for costly metals like aluminium.

Mining and extraction can cause the destruction of habitats.

True.

Recycling decreases the amount of waste produced and therefore space at landfill sites.

Two disadvantages of recycling metals include:

• Materials need to be collected and transported which requires energy and fuel

• Workers, vehicles and worksites need to be organised and maintained

• Materials need to be sorted before they can be recycled

• Products made from recycled materials may not always be of the same quality

Sustainability is the ability to maintain ecological and resource balance over time.

Recycling metals is more energy efficient than extracting new metals because it requires less energy to melt and re-mould the metal.

Iron can be recycled together with waste steel by adding both to a blast furnace.

Recycling reduces the use of fossil fuels.

True.

It is much more energy efficient to recycle metals than it is to extract them as melting and re-moulding requires less energy.

When metals are very scarce, they are all worthwhile to recycle.

The missing label is manufacture.

A life cycle assessment (LCA) is an analysis of the overall environmental impact of a product throughout its entire lifetime, from obtaining raw materials to disposal.

The impact of obtaining raw materials on the environment is using up limited resources and damaging habitats.

The impact the manufacturing process can have on the environment is using up land for factories and the use of fossil fuelled machines for production and transport.

False.

Sometimes the costs and energy used in collecting, transporting and recycling metals can be more expensive than extracting new metals.

A bicycle will have a less damaging impact on the environment.

A life cycle assessment evaluates the environmental impact at every stage of a product's life, from obtaining raw materials to manufacturing, use, and disposal.

The impact that disposing of products can have on the environment is using up space in landfill sites.

False.

Iron ore is a finite source which requires a lot of energy to process.

Two disposal options for metals are recycling or storing in a landfill.