Revision notes for AQA GCSE Chemistry Using the Earth's resources and sustainable development. Open the guide for explanations and worked examples. Written against the AQA GCSE Chemistry (8462) specification, so the content matches what's examinable rather than general Chemistry background.
Using the Earth's resources and sustainable development
What you'll learn
- Why humans depend on the Earth’s resources for warmth, shelter, food and transport.
- The difference between finite and renewable resources.
- How natural products can be supplemented or replaced by agricultural and synthetic products.
- How to interpret resource data from charts, graphs and tables, including orders of magnitude.
The big picture: why resources matter
Everything you use has come from somewhere. Your food, clothes, phone, home, heating, electricity and transport all depend on materials and energy taken from the Earth.
Resources can come from the land, oceans or atmosphere. Chemistry helps us process these resources into useful products, such as fuels, metals, plastics, fertilisers, medicines and building materials.
Definition
Natural resource
A natural resource is a material or substance found in the environment that humans can use. Examples include water, air, crude oil, metal ores, trees, soil and animals.
Humans use resources to provide:
- warmth — fuels, electricity, insulation materials
- shelter — timber, bricks, glass, concrete, metals, plastics
- food — crops, livestock, fish, fertilisers, water
- transport — fuels, metals, rubber, plastics, batteries
Natural, agricultural and synthetic products
Some products are taken directly from nature, but many are now supplemented or replaced by products made through farming or chemical processes.
Natural products
A natural product is obtained from living things or from the Earth without being fully manufactured from other raw materials.
Examples include:
- cotton from cotton plants
- wool from sheep
- timber from trees
- natural rubber from rubber trees
- fuels such as wood, coal, crude oil and natural gas
Agricultural products
Agriculture means farming plants and animals to produce useful resources. Agriculture supplements natural resources because instead of only collecting what grows naturally, humans deliberately grow crops and raise animals.
Examples include:
- wheat, rice and potatoes for food
- cotton for clothing
- timber from managed forests
- crops grown for biofuels
- livestock for meat, milk, leather and wool
Chemistry supports agriculture by producing fertilisers, pesticides and materials for irrigation systems and greenhouses. These can increase food production, but they must be used carefully to avoid pollution and waste.
Synthetic products
Definition
Synthetic product
A synthetic product is made by chemical processes rather than taken directly from nature. Many synthetic products are made from raw materials such as crude oil, natural gas, air, water and minerals.
Examples of natural products being replaced or supplemented include:
- cotton or wool clothing supplemented by polyester and nylon
- natural rubber supplemented by synthetic rubber for tyres
- timber replaced in some uses by plastics, metals, concrete or composite materials
- natural dyes replaced by synthetic dyes
- leather replaced by synthetic polymers in some shoes, bags and seats
Key Idea
Natural is not automatically better
A natural product can still cause environmental damage if it is overused, transported long distances or produced using lots of land and water. A synthetic product can be useful, but it may depend on finite raw materials and create waste.
Finite resources
A finite resource is one that is being used up faster than it is replaced. Many finite resources took millions of years to form, so they cannot be replaced on a human timescale.
Definition
Finite resource
A finite resource is a resource that exists in limited supply and cannot be replaced quickly enough to keep up with human use.
Common GCSE examples include:
- crude oil
- coal
- natural gas
- metal ores
- limestone and other minerals
- uranium used as nuclear fuel
Finite resources are processed to provide energy and materials. For example, crude oil is separated into fractions to make fuels and chemical feedstocks. Metal ores are mined and processed to extract metals.
When methane in natural gas burns, it transfers energy for heating and electricity generation:
CH4(g)+2O2(g)→CO2(g)+2H2O(l)\text{CH}_4\text{(g)} + 2\text{O}_2\text{(g)} \to \text{CO}_2\text{(g)} + 2\text{H}_2\text{O(l)}CH4(g)+2O2(g)→CO2(g)+2H2O(l)Once a fuel has been burned, it cannot simply be reused as the same fuel. That is one reason fossil fuels are finite energy resources.
Common Mistake
Natural does not mean renewable
Crude oil, coal and natural gas are natural resources, but they are finite because they form over millions of years and are used much faster than they are replaced.
Renewable resources
A renewable resource is replaced naturally on a timescale short enough for human use, as long as it is managed properly.
Definition
Renewable resource
A renewable resource is a resource that can be replaced at about the same rate as it is used, or faster, on a human timescale.
Examples include:
- timber from replanted forests
- crops grown for food or biofuels
- water renewed by the water cycle
- wind and solar energy
- some fish stocks, if fishing is controlled
Renewable does not mean unlimited. If trees are cut down faster than they are replanted and grown, timber use becomes unsustainable. If water is polluted or taken from underground stores faster than it is replaced, clean water can become scarce.
Tip
A quick classification test
Ask: How fast does it form compared with how fast humans use it? If formation is much slower than use, it is finite. If replacement keeps up with use on a human timescale, it is renewable.
Example
Classifying resources from information
A question gives you three resources:
- Resource A is crude oil, which forms over millions of years and is burned as fuel.
- Resource B is timber from a forest where trees are replanted and allowed to regrow before harvesting.
- Resource C is groundwater from an aquifer that refills by 10 million cubic metres per year, but humans remove 25 million cubic metres per year.
-
Compare formation or replacement time with human use. Resource A forms over millions of years, so human use is far faster than replacement.
-
Check whether the replacement rate keeps up with use. Resource B is replanted and regrown before harvesting, so the supply can continue if the forest is managed properly.
-
Use the data for Resource C. Since 25 million cubic metres are removed but only 10 million cubic metres are replaced each year, use is greater than replacement. Resource C is being used unsustainably, even though water itself is part of a renewable cycle.
Sustainable development
Humans need resources, so the aim is not simply “use nothing”. The aim is to use resources in a way that supports people now without damaging the ability of people in the future to meet their needs.
Definition
Sustainable development
Sustainable development is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
In chemistry, sustainable development can involve:
- improving industrial processes so they use less energy
- using catalysts to reduce temperatures and pressures needed in reactions
- recycling metals and plastics where possible
- designing longer-lasting or biodegradable materials
- treating water so it is safe to drink
- reducing waste gases and pollution
- improving fertilisers so crops grow well with less waste
Key Idea
Chemistry and sustainability
Chemistry helps society make useful products from resources, but chemists also try to reduce waste, save energy, limit pollution and find alternatives to finite resources.
Interpreting resource data
In exams, you may be given a chart, graph or table about resources. Your job is to extract the important information and use it to support a conclusion.
Always check:
- what the resource is
- whether the data show total use, use per person, percentage use or cost
- the units on the axes or table headings
- whether the data are for one country or the whole world
- whether the time period is one year, ten years or another interval
For example, a graph might show that a country’s use of renewable energy has increased. That does not automatically mean its use of fossil fuels has decreased — both could have increased if total energy demand has risen.
Tip
Reading charts carefully
Before comparing bars or points, read the axis label and unit. “Million tonnes” and “tonnes” are not the same scale, and “per person” data can lead to a different conclusion from total national data.
Orders of magnitude
Sometimes resource data contain very large and very small numbers. Instead of focusing on every digit, scientists often compare the order of magnitude.
Definition
Order of magnitude
An order of magnitude is a factor of 10. If one value is three orders of magnitude larger than another, it is about 10310^3103, or 1000, times larger.
This helps you judge whether a difference is small, large or enormous. For example:
- one order of magnitude means about 10 times bigger
- two orders of magnitude means about 100 times bigger
- three orders of magnitude means about 1000 times bigger
Example
Using orders of magnitude
A chart shows annual extraction of two resources:
- aluminium ore: 200 million tonnes per year
- cobalt ore: 0.2 million tonnes per year
Which resource is extracted in the larger quantity, and by how many orders of magnitude?
-
Check the units. Both values are in million tonnes per year, so they can be compared directly.
-
Calculate the ratio of the larger value to the smaller value.
- Interpret the result. Aluminium ore is extracted in a quantity three orders of magnitude larger than cobalt ore. By mass, aluminium ore extraction is much larger, although cobalt could still have serious environmental impacts per tonne.
Common Mistake
Bigger number does not always mean bigger overall impact
A resource used in smaller mass can still be important if it is rare, difficult to extract, toxic, energy-intensive to process or essential for technology.
Bringing it together
For this section, you should be able to look at a resource and explain:
- what humans use it for
- where it comes from
- whether it is finite or renewable
- whether its use is sustainable
- how chemistry helps process it or reduce its environmental impact
The strongest answers usually include a reason, not just a label. For example, “coal is finite because it forms over millions of years and is burned much faster than it forms” is much better than just “coal is finite”.
Exam technique
In the exam
-
When asked to classify a resource, use the information given about rate of formation and rate of use, not just whether it is natural.
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For graphs and tables, read the headings, units and scale before making a comparison.
-
When discussing sustainable development, link your answer to both present needs and future supply, rather than only saying “better for the environment”.
Self review
Check yourself
- Why is crude oil classed as finite even though it is a natural resource?
- Give two examples of natural products that can be replaced or supplemented by synthetic products.
- A resource is replaced by 5 million tonnes per year but used at 12 million tonnes per year. Is its current use sustainable?
Using the Earth's resources and obtaining potable water
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