“化学物质”是一个必要的术语

例举化学物质一词的使用情况，讨论界定化学物质一词的必要性，提出：化学物质是以原子及其聚集体（核-电子体系）为微观实体的，构成占有空间的宏观物体（气体、液体、固体）的东西。建议在辞书里增添化学物质为一词条，建议教学中讨论化学物质的概念。

Chemical Substance Is a Necessary Term

The paper gives samples of the use of chemical substance,and discusses the necessity of defining the term.Chemical substance is the entity of atoms and their aggregates,i.e. nucleus -electron-systems in microscale to build the object occupying space,i.e.gas,liquid and solid in macroscale.The author suggests the term be added in dictionaries and textbooks.