To collect together and increase in quantity.
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.
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.
Materials that are broken down in the environment by microorganisms. Most synthetic polymers are not biodegradable.
A solution of sodium chloride (salt) in water. Brine is produced by solution mining of underground salt deposits.
A piece of equipment used to separate a mixture of liquids and solids by spinning the mixture very fast.
The process of adding chlorine to water to kill microorganisms, so that it is safe to drink.
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.
The movement that occurs when hot material rises and cooler material sinks.
To form crystals, for example, by evaporating the water from a solution of a salt.
Some chemicals dissolve in liquids (solvents). Salt and sugar, for example, dissolve in water.
Splitting up a chemical into its elements by passing an electric current through it.
A change of state from liquid to gas.
A plastic is shaped by being forced through a mould.
To separate a solid from a liquid by passing it through filter paper.
Mixtures of chemicals that give food, sweets, toothpaste and other products their flavours.