Unit 2: Energy and the Environment:

2-Mark Questions

1. Define a fossil fuel.

Model Answer:

A fossil fuel is a non-renewable energy resource formed from the remains of organisms that were buried and subjected to heat and pressure over millions of years.

Why this works:

• Identifies fossil fuel as non-renewable (1 mark)

• Explains formation from buried organic remains over a long period (2nd mark)

4-Mark Questions

2. Explain how coal is formed.

Model Answer:

Coal forms from the remains of plants that lived millions of years ago. These remains accumulated in swampy areas and were buried under layers of sediment. Over millions of years, heat and pressure compressed the organic material and gradually converted it into coal.

Why this works:

• Plant remains identified → 1 mark

• Burial under sediment → 1 mark

• Heat and pressure → 1 mark

• Long time period/conversion into coal → 1 mark

3. Explain how oil and natural gas are formed.

Model Answer:

Oil and natural gas formed mainly from the remains of microscopic marine organisms that accumulated on the seabed. They were buried under layers of sediment and, over millions of years, heat and pressure converted the organic material into oil and natural gas.

Why this works:

• Marine organisms → 1

• Burial by sediments → 1

• Heat and pressure → 1

• Millions of years → 1

6-Mark Questions

4. Discuss the advantages and disadvantages of using nuclear power to generate electricity.

Model Answer:

Nuclear power can generate large amounts of electricity continuously and is not dependent on weather conditions. It also produces very low carbon dioxide emissions during electricity generation compared with fossil fuel power stations. This makes it useful for meeting high energy demand while reducing greenhouse gas emissions.

However, nuclear power produces radioactive waste, which must be stored safely for very long periods because it can be harmful to humans and the environment. Nuclear power stations are also expensive to construct and decommission. There is also a risk of serious environmental damage if a major accident causes radioactive material to escape.

Overall, nuclear power can provide reliable, low-carbon electricity, but the problems of radioactive waste, high costs and accident risks mean that it is not completely environmentally sustainable.

Why This Works:

• Advantages explained, not simply listed.

• Disadvantages explained with consequences.

• Includes environmental + economic considerations.

• Balanced conclusion gives evaluation.

• Matches examiner’s game: knowledge + explanation + evaluation.

8-Mark Questions

5. Evaluate the use of solar power as an alternative to fossil fuels.

Model Answer:

Solar power is a renewable energy resource that uses sunlight to generate electricity. Solar panels convert sunlight into electrical energy without burning fuel. This means that solar power produces very little air pollution or greenhouse gas emissions during operation and does not require a fuel supply that can eventually run out.

Solar power can also be used in remote areas where connection to a national electricity grid is difficult. Once installed, solar panels have relatively low operating costs because sunlight is free. However, solar electricity generation depends on sunlight, so output is lower at night and during periods of heavy cloud. Large-scale solar farms can also require large areas of land, potentially competing with agriculture or natural habitats.

The initial cost of installing solar panels can also be high, although falling technology costs and long-term savings can make solar power economically attractive. Energy storage, such as batteries, can help overcome the problem of intermittent supply but increases costs.

Overall, solar power is an important alternative to fossil fuels because it is renewable and has low emissions during operation. However, it is most effective when combined with energy storage and other energy sources to provide a reliable electricity supply.

Why This Works:

• Describes how solar power works

• Environmental advantages

• Economic advantages

• Environmental limitations

• Reliability limitation

• Management solution

• Final judgement based on several factors

10-Mark Questions

6. “Reducing energy consumption is more important than developing new energy resources.” Discuss this statement.

Model Answer:

Reducing energy consumption can be an effective way of managing energy resources because it decreases the amount of energy that needs to be produced. For example, insulating buildings reduces heat loss, while energy-efficient appliances and vehicles require less energy to provide the same service. This can reduce energy costs and decrease the amount of fossil fuels burned.

Education can also encourage people to conserve energy by switching off unused electrical devices, reducing unnecessary travel and choosing efficient products. Government transport policies, such as improving public transport, can reduce fuel consumption and emissions from vehicles. These strategies can often be introduced without completely replacing existing energy infrastructure.

However, global energy demand is still likely to increase because of population growth, industrialization, urbanization and rising wealth. Reducing consumption may therefore not be enough to meet future demand. Developing new energy resources, particularly renewable resources such as solar, wind, hydro-electric and geothermal power, can provide additional energy while reducing dependence on fossil fuels.

New technologies may also improve energy storage and make renewable resources more reliable. However, developing new infrastructure can be expensive and some renewable energy sources have environmental impacts or depend on weather conditions.

Overall, reducing energy consumption should be a priority because avoiding unnecessary energy use is often cheaper and reduces environmental impacts immediately. However, it cannot meet all future energy needs on its own. The most effective strategy is to combine energy conservation with the development of renewable and other low-carbon energy resources.

Why This Works:

This is exactly the kind of answer that can score highly because it doesn't blindly agree with the statement.

It evaluates: reduce demand → benefits → limitations → develop new resources → benefits → limitations → judgement.

QUESTIONS DONE BY FARIDA SABET

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