Year 10 Science · Unit 2 · Lesson 7
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Learning Goals
Read the graph
The bar chart below shows the relative rate of hydrogen gas produced when five metals are each added to hydrochloric acid (HCl). Study the data and answer the questions.
Data: Adapted from standard metal reactivity series experiments (RACI, 2022)
(a) Which metal reacts most vigorously with HCl, and which shows no reaction at all? Explain what this tells you about their positions in the reactivity series.
(b) Zinc reacts faster with HCl than iron does. Using this data, predict whether zinc would displace iron from iron(II) chloride solution. Write the word equation for this reaction if it occurs.
(c) Galvanised iron (coated with zinc) is used in Australian building materials and fencing. Using the data above, explain why zinc provides effective protection for iron, even when the zinc coating is scratched and both metals are exposed.
Real-world context
BHP's Olympic Dam mine in South Australia and several copper mines in Queensland use hydrometallurgy to extract copper from low-grade ore. In one method, copper sulfate (CuSO₄) solution, made by leaching ore with acid, is placed in contact with iron scrap metal. A displacement reaction occurs, depositing solid copper. This technique, used in Australia since the 1990s, is more energy-efficient and less polluting than traditional smelting.
(a) Write the word equation for the displacement reaction that occurs when iron scrap is added to copper sulfate solution. Identify which metal is displaced and which enters solution.
(b) Describe two observable changes that would occur in the reaction vessel when iron scrap is added to blue copper sulfate solution. Explain the chemistry behind each change.
1. Explain why gold (Au), which is below copper in the reactivity series, is found as a free metal (nuggets) in nature, while aluminium is only found as a compound (e.g. in bauxite ore). Use the reactivity series concept in your answer.
Wrap Up
In one sentence, what was the main idea of this lesson?