The evolution of fundamental concepts in organic chemistry: Hydrocarbons in Iranian secondary school chemistry textbooks and their information content and importance based on shannon entropy

Articles in Press

Document Type : Original research

Authors

Department of Chemistry Education, Farhangian University, P.O. Box 14665-889, Tehran, Iran

10.48310/chemedu.2026.22062.1407

Abstract

Background and Objectives: This study examines the changes in the basic concepts of the chemistry of different branches of hydrocarbons (alkanes, alkenes, alkynes, and aromatics) in high school chemistry textbooks from 1971 to 2021. Methods: This applied study, following a historical method, uses content analysis. Shannon entropy is applied to data processing and validation. Textbooks from 1975, 1985, 1999, 2009, and 2019 were samples. Findings: The concepts were extracted and counted, and their frequencies were calculated. The results show that in 1975 aromatics had the highest frequency (32.04%) and alkenes the lowest (20.24%). In 1985, aromatics and alkenes were highest (28.07%) and alkynes lowest (21.05%). In 1999, alkenes were highest (29.41%) and alkynes lowest (19.61%). In 2019, alkanes were highest (50.00%) and aromatics lowest (9.09%). In 2019, alkenes were the highest (50.00%) and alkynes and aromatics lowest (9.09%). Conclusion: Comparisons across branches show alkanes peaked in 1999 (50.00%) and were lowest in 1975 (22.81%). Alkenes peaked in 2019 (50.00%) and were lowest in 1985 (20.24%). Alkynes peaked in 1975 (22.62%) and were lowest in 2019 (9.09%). Aromatics peaked in 1975 (32.54%) and were lowest in 2019 (9.09%). Shannon entropy analysis shows alkenes had the highest information content and also importance, and aromatics had the lowest. Across years, the highest information content was in 1985 and the lowest in 2019. The highest importance was in 2019 and the lowest in 1975.

Keywords

Research in Chemistry Education

Articles in Press, Accepted Manuscript
Available Online from 20 March 2026

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