CHEMICAL

[adjective]The chemical industry produces such things as petrochemicals, drugs, paint and rubber.The government has said that it will never use a nuclear bomb except against a chemical attack (= an attack using chemical weapons).Chemical engineering is the design and operation of machinery used in industrial chemical processes.A chemical equation is a symbolic representation of the changes which happen in a chemical reaction.A chemical formula is the representation of a substance using the symbols of its elements.H2O is the chemical formula for water.A chemical reaction is a process in which the atomic or molecular structure of a substance is changed.When potassium is added to water, a violent chemical reaction takes place.Chemical warfare is the use of poisonous gases and other harmful chemicals against enemy forces.Chemical weapons are substances such as poisonous gases, rather than explosives, which can be used to kill or injure people.Almost all countries say they want to ban the use of chemical weapons.