Download Learning objectives: Recall the reactivity of magnesium, zinc, iron

Homework task HC6.5.1
Lesson reference: C6.5 Redox reactions
Redox reactions
Learning objectives:
 Recall the reactivity of magnesium, zinc, iron, and tin from most to least
reactive.
 Describe oxidation and reduction in terms of gain or loss of oxygen.
 Predict and explain displacement reactions between metals and metal salt
solutions.
 Explain oxidation and reduction in terms of loss or gain of electrons (H).
 Explain displacement reactions as examples of redox reactions (H).
Suggested time:
30–45 minutes
Name: ________________________________ Date: ______________________
Displacement reactions
A List iron, magnesium, tin, and zinc in order of reactivity. Put the most reactive
first.
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B Copper is more reactive than silver. Copper can displace silver from silver
compounds. For example, when a piece of copper is put into silver nitrate
solution, it becomes coated with silver and copper nitrate forms.
i Write a word equation to describe the reaction between copper and silver
nitrate.
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ii
Predict what will happen when a piece of silver is dipped into copper
nitrate solution. Give a reason for your answer.
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C Siobhan carried out an investigation. She wanted to find out what happens to
the temperature when a metal reacts with copper(II) sulfate solution. Siobhan
measured 20 cm3 of copper(II) sulfate solution into a boiling tube, recorded
the temperature of the solution, then added a spatula of metal powder. She
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stirred the mixture with a thermometer, and recorded the maximum
temperature reached. The table shows her results.
i
Metal
Start temperature
(°C)
End temperature
(°C)
iron
20
34
tin
19
29
zinc
20
42
Temperature
change (°C)
Calculate the temperature change during each reaction.
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ii
Explain whether the reactions are exothermic, or endothermic.
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iii List the metals in order of increasing temperature change. What do you
notice?
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iv Predict, giving reasons, what would happen if Siobhan used magnesium
powder in her investigation.
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D Aluminium reacts with iron(III) oxide, forming aluminium oxide and iron, in a
vigorous reaction called the thermite reaction.
i Write a word equation for the reaction.
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ii
Identify the reactant that is oxidised, and the reactant that is reduced.
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574
Extension
E
Aluminium is more reactive than lead. A displacement reaction happens when
a piece of aluminium is dipped into lead nitrate solution, Pb(NO3)2(aq).
i The formula for aluminium ions is Al3+ and the formula for nitrate ions is
NO3–. Write the formula for aluminium nitrate.
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ii
Write a balanced symbol equation for the displacement reaction.
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iii Identify, giving reasons, which metal atom or metal ion is reduced, and
which is oxidised.
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© Oxford University Press 2011
This document may have been altered from the original.
575