noun

a chemical substance with a ph value (=a measure used in chemistry) of less than 7

noun

a chemical used in farming, for example a fertilizer

noun

a chemical substance with a ph value (=a measure used in chemistry) of more than 7

noun

a chemical substance that turns red litmus paper blue. All alkalis are bases.

adjective

producing or containing carbon or coal

noun

a substance that causes a chemical reaction to happen more quickly but is not affected itself. An enzyme is a type of catalyst.

noun

a substance used in chemistry or produced by a process involving chemistry

noun

a chemical that consists partly of chlorine, usually with one other element

noun

a chemical substance that consists of two or more elements that together form a molecule. Each different compound has a fixed ratio of elements. For example the water compound (H2O) consists of two hydrogen atoms and one oxygen atom

noun

a substance that consists of only one type of atom

noun

a natural chemical produced by animal and plant cells that helps reactions and other processes to start

noun

a substance, especially a drug such as lsd, that causes someone to hallucinate

noun

a chemical compound containing water

noun

a chemical substance that contains only hydrogen and carbon, for example methane

noun

one of the forms of a chemical element that have the same atomic number because they have the same number of protons, but have a different number of neutrons, and therefore have a different mass

noun

a chemical element such as silicon that is not a metal but that has some of the qualities that a metal has

noun

a substance consisting of different substances that combine without a chemical reaction

noun

a chemical containing one atom of oxygen in each molecule

noun

a chemical element that is not a metal, for example carbon or oxygen. Non-metals are solids and gases and are not good conductors of heat and electricity.

noun

a chemical that consists of oxygen combined with another substance

noun

a chemical made from petroleum or natural gas

noun

a natural or artificially produced chemical substance consisting of large molecules made of many groups of smaller ones

noun

an enzyme that helps the body to change protein into the substances that it needs

noun

a substance that reacts with another in a chemical reaction

noun

a chemical substance formed from an acid

noun

a substance made from silica mixed with another substance

noun

a substance that has dissolved in a solvent and become part of the liquid so that they form a solution

noun

a liquid that has a solid substance dissolved in it so that it has become part of the liquid

noun

a substance on which a catalyst or enzyme has a particular effect

noun

a salt (=chemical substance) produced from sulfuric acid

noun

a mixture of sulfur and another chemical element

noun

a poisonous substance that causes disease