acid acidity agent air alkali alkalinity alloisomer anion antacid atom atomic particles base biochemical brute matter building block cation chemical chromoisomer component compound constituent copolymer dimer earth element elementary particle elementary unit fire fundamental particle heavy chemicals high polymer homopolymer hydracid hyle hypostasis inorganic chemical ion isomer macromolecule material material world materiality matter metamer molecule monad monomer natural world nature neutralizer nonacid organic chemical oxyacid physical world plenum polymer pseudoisomer radical reagent stuff substance substratum sulfacid the four elements trimer unit of being water