4.2.6Electrochemistry
Energy Resources — Cambridge IGCSE Chemistry 0620 Revision Notes & Topical Questions
5 min read 4 parts Lesson 18 of 20 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 4Non-renewable Resources
Non-renewable resources cannot be replaced on a human timescale once they have been used up.
Fossil fuels
- Fossil fuels Coal, oil and natural gas formed from ancient organic matter, burned to release their chemical energy.
Nuclear fuel
- Nuclear fuel Uranium nuclei are split in a fission reactor, releasing energy from the nuclear store as thermal energy.
Limited supply
- Limited supply Non-renewable resources will eventually run out because they form far more slowly than they are used.
Carbon emissions
- Carbon emissions Burning fossil fuels releases carbon dioxide, which adds to the greenhouse effect and global warming.
Section 2 of 4Renewable Resources
Renewable resources are replaced naturally, although each has limits on where and when it can be used.
Renewable Resources
Solar
- Solar Photovoltaic cells convert sunlight directly into electrical energy, and solar panels can warm water.
Wind
- Wind Moving air turns the blades of a turbine, transferring kinetic energy to electrical energy, which depends on wind speed.
Hydroelectric
- Hydroelectric Water stored at height flows through turbines, converting gravitational potential energy into electricity.
Tidal and wave
- Tidal and wave The movement of sea water turns turbines, using the kinetic and gravitational energy of the oceans.
Geothermal
- Geothermal Heat from hot rocks deep underground is used to heat water or to drive generators.
Section 3 of 4Generating Electricity
Most power stations follow the same basic sequence of energy transfers.
1
A primary energy source, such as burning fuel or moving water, heats water or turns a turbine directly.
2
The turbine spins a generator, which transfers kinetic energy into electrical energy.
3
The electrical energy is sent through the national grid to homes, schools and factories.
4
In appliances, electrical energy is transferred into useful stores such as light, sound and kinetic energy.
Section 4 of 4Exam Checklist & Tips
4.2.6 – Key Points for the Exam
- Renewable resource An energy resource that is replaced naturally and will not run out in human timescales.
- Non-renewable resource An energy resource that cannot be replaced on a human timescale once used.
- Fossil fuel A coal, oil or gas fuel formed from ancient organic matter.
- Turbine A device with blades that is turned by a moving fluid to drive a generator.
- National grid The network of cables that carries electricity from power stations to consumers.
Common Mistakes
- Calling solar or wind a store; they are energy resources, and the energy is transferred into stores.
- Saying renewable sources have no environmental impact at all;
- they still affect land, wildlife and landscapes.
- Confusing the energy source with the energy store that the turbine or appliance transfers energy into.
- Stating that nuclear power is renewable because it is a low-carbon source; nuclear fuel is non-renewable.
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