Chemistry - Supplying and using energy
Supplying and using energy
In our daily lives we take for granted the ready availability of hot water
and lighting, the operation of appliances such as refrigerators, microwave
ovens, televisions and computers and the smooth running of motor vehicles
and public transport. We eat regular meals because our bodies function
better if we do. These are just a few examples of situations whereare an
integral part of our lives.
Most of the energy we utilise on earth can be traced back to the sun. In
photosynthesis, green plants convert solar (light) energy into chemical
energy, which is stored in sugars and other carbon compounds. These plants
become the source of energy for living things. The energy available from
fossil fuels - coal, oil and natural gas - can also be traced back to solar
Energy is a phenomenon that is much easier to point to than to pin down
and describe. You cannot actually see energy when looking at a tankful of
petrol, but you can see the effect of the transformation of the chemical
energy in the petrol when a motor vehicle is moving.
Our dependence on energy supplies ranges from the large scale as in the
operation of large power stations that provide electrical energy for
industry and millions of homes, offices and entertainment venues, to the
small scale batteries which provide electrical energy for watches,
calculators and portable computers.
The label on a packet of breakfast cereal tells you that the energy
content of the cereal is 653 kJ per 45 gram serving. Measurement of the
energy content of foods, and fuels, is an important analytical process.
The role of energy transformations in industrial processes is extensive.
Aluminium, the lightweight metal that we take for granted in drink cans,
packaging, saucepans and building materials, is also extensively used in
motor vehicles and aircraft. Its production from bauxite requires large
quantities of electrical energy. The production of chlorine, hydrogen and
sodium hydroxide also involves the use of electrical energy, as does the
electroplating of materials.
Cutting-edge research continues in fuel cell and battery development, with
both fuel cells and batteries emerging as potential replacements for the
internal combustion engine.
Research continues into increasing the efficiency of the collection and
storage of solar energy.
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