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Humans rely on the Earth to provide everything we need to survive and develop. This lesson introduces the key ideas behind how we use the Earth's natural resources, the distinction between finite and renewable resources, and the concept of sustainable development. These ideas underpin the entire AQA GCSE Chemistry Topic: Using Resources.
A natural resource is a material that comes from the Earth, the sea or the atmosphere and can be used by humans. Humans have always exploited natural resources to provide warmth, shelter, food and transport.
| Type of Resource | Definition | Examples |
|---|---|---|
| Natural resource | A material found in or produced by the Earth that can be exploited by humans | Wood, cotton, stone, crude oil, metal ores |
| Synthetic product | A material made by chemical reactions that does not occur naturally | Plastics, nylon, medicines, fertilisers |
As chemistry has developed, humans have been able to create synthetic alternatives to many natural products. For example:
| Natural Product | Synthetic Alternative | Advantage of Synthetic |
|---|---|---|
| Wool | Polyester / Nylon | Cheaper, more uniform, easier to mass-produce |
| Rubber | Synthetic rubber | More consistent properties, wider availability |
| Leather | PVC / polyurethane | Lower cost, no animal welfare issues |
| Willow bark (aspirin precursor) | Synthesised aspirin | Purer, controlled dosage, mass production |
Exam Tip: The AQA specification expects you to appreciate that chemistry provides the ability to make new materials that improve our quality of life. When asked to evaluate, discuss both benefits and drawbacks of replacing natural materials with synthetic ones.
Resources can be classified based on how quickly they can be replaced:
| Resource Type | Definition | Examples |
|---|---|---|
| Finite (non-renewable) | Resources that are being used up faster than they can be formed; they will eventually run out | Fossil fuels (coal, oil, natural gas), metal ores, minerals |
| Renewable | Resources that can be replenished at the same rate as, or faster than, they are used | Wood (from managed forests), crops, wind, solar, tidal |
graph TD
A[Earth's Resources] --> B[Finite / Non-renewable]
A --> C[Renewable]
B --> D[Fossil Fuels]
B --> E[Metal Ores]
B --> F[Minerals]
C --> G[Wood from managed forests]
C --> H[Crops and biofuels]
C --> I[Wind / Solar / Tidal energy]
style A fill:#e3f2fd,stroke:#1565c0
style B fill:#ffcdd2,stroke:#c62828
style C fill:#c8e6c9,stroke:#2e7d32
style D fill:#ffcdd2,stroke:#c62828
style E fill:#ffcdd2,stroke:#c62828
style F fill:#ffcdd2,stroke:#c62828
style G fill:#c8e6c9,stroke:#2e7d32
style H fill:#c8e6c9,stroke:#2e7d32
style I fill:#c8e6c9,stroke:#2e7d32
Exam Tip: Be careful not to confuse finite with non-existent. Finite resources still exist but are being depleted. The key point is that they form far more slowly than they are consumed — for example, fossil fuels take millions of years to form.
Sustainable development means meeting the needs of the present population without compromising the ability of future generations to meet their own needs. This is one of the most important concepts in this topic.
Sustainable development requires a balance between:
| Factor | What It Means |
|---|---|
| Economic needs | People need jobs, income and affordable products |
| Environmental protection | Ecosystems, habitats and biodiversity must be preserved |
| Social wellbeing | Communities need clean water, clean air and a healthy environment |
Chemistry helps achieve sustainability in several ways:
Farming is one of the most significant ways humans use natural resources. Agriculture provides food for the global population, but it also requires:
| Resource Used in Agriculture | Purpose |
|---|---|
| Land | Growing crops and rearing livestock |
| Water | Irrigation of crops, drinking water for animals |
| Fertilisers | Replacing minerals in soil (nitrogen, phosphorus, potassium) |
| Pesticides | Protecting crops from insect damage |
| Energy | Powering machinery, heating greenhouses, transporting produce |
The challenge is to produce enough food without depleting resources or causing long-term environmental damage. Intensive farming maximises yield but can harm the environment through pollution, soil erosion and habitat destruction.
Exam Tip: AQA may ask you to discuss the competing demands on natural resources. Always consider both sides — humans need resources for development, but over-exploitation damages the environment. A balanced answer that considers sustainability will score highest.
Water is perhaps the most important natural resource. It is used for:
In the UK, most drinking water comes from surface water (rivers, lakes, reservoirs) and groundwater (water stored in permeable rocks called aquifers). Different regions rely on different sources depending on local geology and rainfall patterns.
Exam Tip: When writing about sustainable development, always link your answer to a specific resource or process. Vague statements like "we should be sustainable" will not score marks — you need to explain how and why a particular approach is more sustainable.
A clothing manufacturer is deciding whether to make a new range of T-shirts from cotton (a natural product) or polyester (a synthetic product). The company wants to make a sustainable choice.
| Factor | Cotton | Polyester |
|---|---|---|
| Source | Grown from a plant (cotton bush); a renewable crop | Made from crude oil; a finite resource |
| Water use | Very high — approximately 2,700 litres per T-shirt for irrigation | Low in manufacture but microplastic release in washing |
| Energy in production | Moderate (growing, harvesting, ginning, spinning) | High (cracking, polymerisation, extrusion) |
| Biodegradability | Fully biodegradable | Not biodegradable; persists in landfill for centuries |
| Recyclability | Limited (fibre length shortens each cycle) | Can be recycled back to PET flake |
A balanced conclusion must weigh both options. Cotton is renewable and biodegradable, which supports sustainable development, but its huge water footprint can stress finite fresh water supplies in arid growing regions. Polyester starts from a finite resource (crude oil) and does not biodegrade, yet it uses less water and can be recycled. Neither is "greener" in every category — the correct exam answer is that sustainability depends on which impacts you prioritise.
Common mistake: Writing "cotton is natural so it is always better for the environment". AQA examiners reward candidates who recognise that growing crops also has environmental costs and that an LCA-style comparison is needed.
Aluminium is extracted from the ore bauxite by electrolysis. Bauxite is a finite resource — there is a fixed amount in the Earth's crust. However, aluminium can be recycled indefinitely, turning a finite supply into something closer to a renewable flow. This is a classic example of how chemistry supports sustainable development.
| Stage | Energy per kg of aluminium (approximate) |
|---|---|
| Extraction from bauxite by electrolysis | 200 MJ |
| Recycling from scrap | 10 MJ |
Recycling uses roughly 5 percent of the energy of primary extraction. The same idea applies to steel, copper and glass: although the raw materials are finite, efficient recycling stretches the supply across many generations.
graph LR
A[Finite bauxite ore] -->|Electrolysis<br>200 MJ/kg| B[Aluminium metal]
B --> C[Used in products<br>cans, frames, foil]
C --> D[Collected for<br>recycling]
D -->|Melting<br>10 MJ/kg| B
style A fill:#ffcdd2,stroke:#c62828
style B fill:#bbdefb,stroke:#1565c0
style C fill:#fff9c4,stroke:#f57f17
style D fill:#c8e6c9,stroke:#2e7d32
Common mistake: Saying "aluminium is renewable". It is not — the ore is finite. What makes aluminium sustainable is the efficient recycling loop, not the original resource.
The Haber process converts atmospheric nitrogen and hydrogen into ammonia, which is then turned into fertilisers. Without it, global food production would not meet demand. However, the Haber process:
Sustainability in this context involves balancing food security for a growing population against fossil fuel use and greenhouse gas emissions. Research into "green ammonia" (using hydrogen from electrolysis of water powered by renewables) illustrates how chemistry is actively looking for sustainable alternatives.
Exam-style question (4 marks): Explain what is meant by sustainable development and describe how recycling aluminium supports it.
Grade 4–5 answer: Sustainable development means meeting today's needs without harming the future. Recycling aluminium is good because it saves energy and means we do not have to dig up as much bauxite. This is better for the environment.
Grade 8–9 answer: Sustainable development means meeting the needs of the current generation without compromising the ability of future generations to meet their own needs. Bauxite, the ore of aluminium, is a finite resource, so extracting it by electrolysis depletes the Earth's reserves and uses around 200 MJ of energy per kilogram. Recycling aluminium requires only about 10 MJ per kilogram (around 5 percent of primary extraction energy), so it conserves the finite ore, reduces carbon dioxide emissions associated with electricity generation, and cuts the need for mining. Together these effects preserve resources and reduce environmental impact, which directly supports sustainable development.
Wood is often held up as the classic renewable material, but renewability depends on how the forest is managed.
| Practice | Outcome |
|---|---|
| Planting one new tree for every tree felled | Net forest area preserved; genuinely renewable |
| Clear-felling with no replanting | Deforestation; biodiversity loss; soil erosion |
| Harvest from certified sustainable forests (FSC) | Balance of economic, environmental and social concerns |
| Use of fast-growing coppice species (willow, bamboo) | Very short cycle times; can feed biomass energy |
The AQA specification highlights that a resource only counts as renewable when its rate of use does not exceed its rate of replacement. This is a subtle but important examination point.
Two of the most important contributions of chemistry to human welfare link directly to this topic:
| Contribution | Link to spec |
|---|---|
| Producing potable water | 5.10.1.2 |
| Treating waste water | 5.10.1.3 |
| Extracting metals such as copper from low-grade ores | 5.10.1.4 |
| Synthesising ammonia in the Haber process to make fertilisers | 5.10.4 |
| Designing new alloys, ceramics, polymers and composites | 5.10.3 |
Each of these interventions helps meet the needs of a growing population without excessive impact on finite resources — the working definition of sustainable development.
Exam Tip: AQA loves questions that ask you to "give two examples of how chemists contribute to sustainable development". Potable water, fertilisers via the Haber process, and recycling are safe, high-scoring answers.
AQA alignment: This content is aligned with AQA GCSE Chemistry (8462) specification section 5.10 Using resources — specifically 5.10.1.1 Finite and renewable resources, 5.10.2.1 Life cycle assessment, 5.10.2.2 Ways of reducing use of resources. Assessed on Paper 2.