12.5Chapter 12: Chemical Reactions 3 and Rates

Extracting copper — Alhussan Chemistry - Stage 9 Revision Notes & Topical Questions

5 min read 8 parts Lesson 5 of 13 2 quizzes

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Lesson summary

12.5 Extracting copper — Malachite Decomposition and Displacement — Alhussan International Academy — Chemistry (Stages 7–9) notes: Describe how copper is obtained from malachite and from waste, and the environmental impacts of copper mining and extraction.Uses — copper makes wate…

Reactivity
Observations
Reduction with carbon
Idea behind both routes
Percentage yield
Improvements

Part 1 of 6Copper and malachite

Uses

Uses copper makes water pipes, electric wires, electrical wiring, heat exchangers and coins.

Malachite

Malachite a green ore containing copper carbonate.

Reactivity

Reactivity copper is low in the reactivity series, so it can be obtained from its compounds fairly easily.

Part 2 of 6Stage 1: thermal decomposition

1Method

Method heat powdered malachite strongly in a boiling tube fitted with a delivery tube leading to limewater.

2Observations

Observations the green powder turns black and the limewater goes cloudy.

3Equation

Equation copper carbonate → copper oxide + carbon dioxide.
The black solid is copper oxide, and the cloudy limewater shows carbon dioxide was released.
The mass of solid decreases as the gas escapes.

Part 3 of 6Stage 2: getting the copper

1Reduction with carbon

Reduction with carbon mix copper oxide with carbon powder and heat strongly in a crucible.
copper oxide + carbon → copper + carbon dioxide, and pink-brown copper is seen.

2Displacement

Displacement add the copper oxide to warm dilute sulfuric acid to make blue copper sulfate solution.
copper oxide + sulfuric acid → copper sulfate + water.
Then add a more reactive metal such as iron or zinc: iron + copper sulfate → iron sulfate + copper.

3Idea behind both routes

Idea behind both routes copper is a low-reactivity metal, so a more reactive substance can remove its oxygen or take its place.

Route	Advantages	Disadvantages
Heating with carbon	Few steps	Needs high temperature, makes carbon dioxide
Displacement	Lower temperature	Uses acid, produces waste solution

Part 4 of 6Safety and evaluation

Safety

Safety wear eye protection, hold the boiling tube at an angle pointing away from people and heat gently at first to avoid spitting.
Remove the delivery tube from the limewater before stopping heating to prevent suck-back, which could crack the tube.
Dilute sulfuric acid is an irritant, and copper compounds are harmful if swallowed.

Percentage yield

Percentage yield actual mass ÷ expected mass × 100.

Yields are below 100% because some oxide does not react, some is lost in transfer or filtering, and copper may re-oxidise on heating in air.

Improvements

Improvements grind the reactants finely, heat in a closed tube and use a little excess carbon.

Part 5 of 6Environmental impacts of copper mining

Waste rock

Waste rock huge piles of waste rock cover land that cannot be used for farming or houses, and few plants and animals survive.

Pollution

Pollution noisy lorries and machinery pollute the air, and acidic water must be managed so rivers are not polluted.

Energy and gases

Energy and gases mining and extraction need huge amounts of energy and make large amounts of greenhouse gases such as carbon dioxide,
- which cause climate change.

Increasing demand

Increasing demand solar cells and wind turbines are connected by copper cables, so more renewable electricity increases world demand for copper.

Part 6 of 6Better ways of extracting copper

Advantages

Advantages compared with mined ore, these methods are less harmful to the environment, need less energy and cost less.

Recycling

Recycling companies collect used copper objects such as water pipes and computer parts and heat them to 1085 °C.
The copper melts and is poured into moulds, where it freezes as ingots that are sold and made into new objects.
This method has been used for hundreds of years.

Extracting from waste

Extracting from waste some devices and mine waste contain very small amounts of copper.
Spray sulfuric acid onto the waste to make copper sulfate solution.
Add waste iron, which is higher in the reactivity series, to displace copper: iron + copper sulfate → iron sulfate + copper.

Phytomining

Phytomining some plants grow well on soil mixed with copper ore waste, and copper ions enter through the roots and are stored in their cells.
The crop is harvested and burned, and the ash is rich in copper compounds.

Bioleaching

Bioleaching bacteria are used to extract copper from low-grade ore.

Key terms

Term	Meaning
Malachite	a green copper carbonate ore.
Reduction	the removal of oxygen from a compound.
Displacement	one metal replacing another in a compound.
Limewater	a test solution for carbon dioxide.
Phytomining	using plants to take up metal ions from soil so the metal can be extracted.
Ingot	a block of metal cast in a mould.

Avoid these mistakes

Saying the black solid is carbon — the black solid is copper oxide.

Saying copper is more reactive than iron — iron is more reactive and displaces copper.

Forgetting to use dilute acid — concentrated acid is more hazardous.

Writing that copper carbonate gives copper directly — it first decomposes to copper oxide.

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Last updated: 13 October 2026