Abstract
The concept of the "amount of a substance" occupies an important position in modern chemistry, and it is necessary to understand quantitative relations in chemical reactions. However, the concept is very difficult to understand for senior high school students. Several teaching aids have mainly been employed by some school teachers and science education researchers in order to provide a better understanding of the concept. But it is known that Japanese high school students do not like the term "mole". In this paper, we first clarify the problem based on the historical background concerning the concept of the "amount of a substance" and describe the adoption of the SI unit to improve the situation. Second, the types of descriptions of the "amount of a substance (mole)" are investigated in high school chemistry textbooks. It is also clarified in this paper how chemistry education has been influenced by the academic transition from the amount of a substance to the unit "mole". Appropriate treatment of the concept is then proposed by the authors through consideration of the above results and the introducting the concept of particle picture of substances.
