Reactivity of Metals (AQA GCSE Chemistry: Combined Science)

This question is about oxides of metals.

Sodium oxide is produced when sodium is heated in oxygen. The balanced equation for the reaction is as follows:

4Na + O₂ ⟶ 2Na₂O

Why is this considered an oxidation reaction?

In terms of oxygen, describe what happens to a substance that undergoes reduction?

A student investigated the reactivity of three different metals by reacting the metals with each other's sulfates in solution.

This is the method that the student used.

1. Place 1 g of the metal powder in a test tube.
2. Add 10 cm³ of the metal sulfate solution.
3. Shake slightly, wait 1 minute and observe.
4. Repeat using the other metal sulfates and metals

The student tabulated her results as shown in Table 1 below. She placed a tick in the table if there was a reaction and a cross if there was no reaction.

Table 1

Give one observation the student could make that shows there is a reaction between zinc and copper sulfate.

Use the results shown in the table above to place the three metals in order of reactivity.

Suggest one reason why the student should not use potassium in this investigation.

Zinc is extracted from zinc oxide by reduction.

Which element acts a reducing agent during this process?

Table 1 provides information about some metals.

Table 1

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.

This question is about the extraction and use of copper.

Most of the copper extracted globally is used in the production of electric circuits and wiring.

Figure 1 shows how impurities in the copper affect its electrical conductivity.

Figure 1

Copper that is extracted by smelting is approximately 99% pure. 

This is then purified further to 99.9999% by electrolysis.

Use values from Figure 1 to explain why copper is purified to 99.9999%.

Copper can be extracted from solutions of copper salts by the addition of iron. 

Use your knowledge of the reactivity series to explain why.

Explain which species is reduced in the reaction between magnesium and copper (II) sulfate.

Mg + CuSO₄ ⟶ Cu + MgSO₄

Your answer should include the half equation for the reduction.

Copper does not react with sulfuric acid but other metals such as iron or aluminium do. 

Explain this trend in terms of the reactivity series and the tendency to form a positive ion.

This question is about redox reactions.

Copper (II) oxide and hydrogen gas react to produce copper and water.

Write a balanced symbol equation for the reaction including state symbols.

__________ + __________ → __________ + __________

Identify the chemical species being oxidised and the species being reduced.

The balanced equation for the displacement of copper from copper (II) sulphate by zinc is shown:

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

Write the overall ionic equation and both half equations for the reaction.

Zinc reacts with hydrochloric acid. 

Which statement is not true for this reaction? 

A student was investigating the reactivity of different metals in hydrochloric acid. 

What must the student keep constant in this investigation to make it a fair experiment?

A student investigated simple cells using the apparatus shown in Figure 1.

Figure 1

• A positive voltage is measured if metal 2 is more reactive than metal 1.
• A negative voltage is measured if metal 2 is less reactive than metal 1.
• The magnitude of the voltage produced depends on the reactivity of the metals.
• The bigger the difference in reactivity, the larger the voltage produced.

The student’s results are shown in Table 1 below:

Table 1

The half equation for the reaction which occurs at the zinc electrode in the cell with copper and zinc electrodes is:

Zn → Zn²⁺ + 2e⁻

State whether zinc is oxidised or reduced and explain why.

Write down the half equation that occurs at the other electrode in the situation described in part (a).

Look at the table above to determine which metal is the least reactive?

Give a reason for your answer.

Metal ____________________

Reason ______________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

Predict the voltage that would be obtained for a simple cell with iron as metal 1 and copper as metal 2.

Explain your answer.

A student observed the reaction between copper(II) sulfate solution and zinc. 

Which observations are correct for this reaction?

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.

This question is about displacement reactions.

In their first experiment, a student uses the following method to investigate the reaction between zinc and copper (II) sulfate solution.

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

1. Measure exactly 25.0 cm³ of 79.8 g / dm³ copper (II) sulfate solution into a polystyrene cup
2. Record the initial temperature of the solution
3. Add about 5 g of zinc powder
4. Stir the mixture
5. Record the highest temperature reached

Show that zinc is not the limiting reactant.

Relative atomic masses (A_r):     Zn = 65,     Cu = 63.5,     S = 32,     O = 16

Describe two observations that you would expect to see during the displacement reaction between zinc and copper (II) sulfate.

Explain whether the zinc is oxidised or reduced in this displacement reaction.

Your answer should include a half equation.

In a second experiment, the student places 5 g of copper powder into a beaker containing nickel sulfate solution. 

No reaction occurs.

Explain why the order of reactivity for copper, nickel and zinc cannot be determined from these two experiments.

This question is about the reaction between lead (II) nitrate solution and potassium chromate solution.

Lead (II) nitrate solution and potassium chromate solution react to form a yellow precipitate of lead (II) chromate and potassium nitrate solution.

Complete the equation by adding the state symbols.

Pb(NO₃)₂ (___) + K₂CrO₄ (___) → PbCrO₄ (___) + 2KNO₃ (___)

The formula of the chromate ion is .

Explain why this reaction is not a redox reaction.

Describe how a pure, dry sample of solid lead (II) chromate can be obtained at the end of the investigation.

Lead nitrate was used in the production of many paints.

Suggest why lead nitrate has been replaced by titanium dioxide in the production of many paints. 

A student investigated the temperature change in displacement reactions between metals and iron sulfate solution.

The student’s results are shown in Table 1.

Table 1

Explain what type of graph should be plotted from the student's results.

Using the student's results, explain whether it is possible to rank the metals from most to least reactive or not.

You have been asked to make one adaptation to the experiment so that you can find the position of an unknown metal in the reactivity series.

Describe the method, including your adaptation, to determine the position of an unknown metal in the reactivity series.

Your adapted method should give valid results.