Key words for c3

Accumulate

To collect together and increase in quantity.

Alkali acts

The Acts of Parliament passed in the UK in order to control levels of pollution. They led to the formation of an Alkali Inspectorate, which checked that at least 95% of acid fumes were removed from the chimneys of chemical factories.

alkali

A compound that dissolves in water to give a solution with a pH higher than 7. An alkali can be neutralised by an acid to form a salt. Solutions of alkalis contain hydroxide ions.

biodegradable

Materials that are broken down in the environment by microorganisms. Most synthetic polymers are not biodegradable.

brine

A solution of sodium chloride (salt) in water. Brine is produced by solution mining of underground salt deposits.

centrifuge

A piece of equipment used to separate a mixture of liquids and solids by spinning the mixture very fast.

chlorination

The process of adding chlorine to water to kill microorganisms, so that it is safe to drink.

chlorine

A pale green toxic gas, used to bleach paper and textiles, and to treat water.

conservation of energy

The principle that the total amount of energy at the end of any process is always equal to the total amount of energy at the beginning – though it may now be stored in different ways and in different places.

convection

The movement that occurs when hot material rises and cooler material sinks.

crystallise

To form crystals, for example, by evaporating the water from a solution of a salt.

dissolve

Some chemicals dissolve in liquids (solvents). Salt and sugar, for example, dissolve in water.

electrolysis

Splitting up a chemical into its elements by passing an electric current through it.

evaporate

A change of state from liquid to gas.

extruded

A plastic is shaped by being forced through a mould.

filter

To separate a solid from a liquid by passing it through filter paper.

flavouring

Mixtures of chemicals that give food, sweets, toothpaste and other products their flavours.

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