Extraction & Uses of Metals (Edexcel IGCSE Chemistry)

Which property belongs to low carbon steels?

This question is about the metal aluminium.

i) Draw a labelled diagram to represent the structure and bonding in a metal.

(2)

ii) Explain why a metal conducts electricity.

(2)

Aluminium is used to make cans for drinks. 

Give two properties of aluminium that make it suitable for this use.

Aluminium is extracted from aluminium oxide (Al₂O₃) by electrolysis.

The electrolyte is aluminium oxide dissolved in molten cryolite.

 i) State why aluminium cannot be extracted by heating aluminium oxide with carbon.

(1)

ii) Aluminium is produced at the negative electrode. The ionic half-equation for the reaction is:  Al³⁺ + 3e⁻ → Al

 State why this is a reduction reaction.

(1)

iii) Complete the ionic half-equation for the reaction at the positive electrode.

(2)

............................... O²⁻ → ................................... + .....................................

Which two properties make aluminium suitable as the metal used as cans for drinks?

Most metals are extracted from ores found in the Earth’s crust.

The method used to extract a metal from its ore is linked to the reactivity of the metal.

Part of the reactivity series is shown below.

Iron ore contains iron oxide.

Iron is extracted from iron oxide by heating the oxide with carbon.

iron oxide + carbon → iron + carbon dioxide

i) In this reaction

(1)

ii) The formula of the iron oxide is Fe₂O₃.

Calculate the maximum mass of iron that can be obtained from 240 tonnes of iron oxide, Fe₂O₃.

(relative atomic masses: O = 16, Fe = 56)

(3)

Aluminium cannot be extracted by heating its oxide with carbon. Aluminium has to be extracted from its oxide by electrolysis. Explain why.

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

Which of the following metals can not be extracted from its ore by reduction?

The table provides information about some metals.

Explain why gold is found in its unreacted form, as the metal itself in the Earth.

The equation below shows one of the reactions in the extraction of zinc.

ZnO + C → Zn + CO

Explain why carbon is used to extract zinc.

Sodium is one of the most abundant metals on Earth but was not extracted until 1807.

Explain, as fully as you can, why this is so.

The reactivity series of metals contains two non-metals. 

State the names of these elements and give one reason why they are included.

The box gives the names of some metals.

i) Identify the metal from the box that burns with a bright white flame.

(1)

ii) In the Earth, metals are found either in ores or as uncombined elements. Explain which metal from the box is most likely to be found as an uncombined element.

(2)

This is the order of reactivity of four metals.

The method used to obtain a metal from its oxide depends on the reactivity of the metal. Two possible methods are

Method 1 heating the metal oxide with carbon

Method 2 electrolysis

Explain which method should be used to obtain lead from lead(II) oxide, PbO. Include an equation for the formation of lead in your answer.

The diagram shows the arrangement of the particles in a pure metal.

Metals are often made into alloys to make them harder.

Explain why alloys are harder than pure metals.

Draw a diagram to support your answer.

The order of reactivity of copper, magnesium and zinc can be determined by the displacement reactions between these metals and solutions of their salts. 

You are provided with 

• Samples of the three metals

• Solutions of copper sulfate, magnesium sulfate and zinc sulfate 

Describe the experiments that can be done to determine the order or reactivity of these metals by displacement reactions.

Metals can be extracted from ores found in the Earth’s crust.

Explain why aluminium cannot be extracted from its ore by heating with carbon but can be extracted by electrolysis.

Titanium is extracted from its ore in several stages.

In the first stage, titanium chloride is formed as a gas.

The gas is cooled to form liquid titanium chloride containing dissolved impurities.

Suggest how pure titanium chloride could be separated from the impurities.

After this reaction, there is a mixture of the solids magnesium, titanium and magnesium chloride.

Titanium does not react with dilute hydrochloric acid.

Suggest a simple method to separate titanium from the mixture.

Tungsten is a useful metal. It has the chemical symbol W.

One method of extracting tungsten involves heating a tungsten compound, WO₃, with hydrogen. Write the balanced symbol equation for this reaction.

Explain why the reaction in part (a) is described as reduction.

Tungsten alloyed with nickel and copper can be used to make protective covers for electrical sensors and missile guidance systems. Explain why this alloy is stronger than pure tungsten. 

An ore of tungsten is Scheelite. The composition of this ore is 13.9% of calcium, 63.9% of tungsten and the remainder is oxygen. Calculate the empirical formula for this ore of tungsten.

This question is about titanium.

Titanium is highly valued as a metal due to its high tensile strength, resistance to corrosion and high melting point. It is also as strong as steel but 45% lighter.

Titanium is most commonly produced by using the following batch process from its ore, rutile (titanium oxide). This process can take up to 17 days.

1. Titanium oxide reacts with chlorine

2. Titanium chloride is placed in a reactor with magnesium at 900 ^oC in a sealed container for 3 days 

3. The reactor is allowed to cool

4. The titanium and magnesium chloride are separated by hand

Carbon cannot be used in the reactor as a replacement for magnesium, as there is no reaction.  

Explain what this suggests about the relative reactivities of carbon, magnesium and titanium.

Titanium reactors produce about 41.67 kg of titanium per hour whereas iron blast furnaces produce about 20 000 tonnes of iron per hour. 

Calculate how many times more iron is produced per hour. Show your working. 

Give your answer to three significant figures.

There are several applications where titanium is used instead of steel. However, the cost of titanium limits its uses. 

Explain why titanium costs more than steel to produce.

It is suggested that the titanium end product could be purified by washing it with water to remove the magnesium chloride. 

Explain why this suggestion is not suitable.

Steel is formed from iron and carbon and is widely used in the construction industry.

i) Explain why steel alloys are used in preference to iron.

(1)

ii) State a use of stainless steel.

(1)

Both iron and steel have typical metallic structures - a lattice of positive ions and a sea of electrons.

i) Explain why iron and steel have high melting points.

(2)

ii) Explain why, when a force is applied to a piece of steel, it does not break but changes its shape.

(2)

Brass is an alloy of two metals, copper and zinc.

Which statement is correct, tick (✔) one box.