E = mc~2 for the Chemist:When Is Mass Conserved?

摘要

In 1905 Albert Einstein derived an equation that expresses a relationship between mass and energy (1).These two quantities,which were previously thought to be independent of one another,became linked by E = mc~2.In spite of its simplicity,the equation is often misinterpreted in textbooks and the popular science literature.Authors in both physics (2-12) and chemistry (13-19) have attempted over many years to correct the misconceptions.This article is one such effort.It asks to what extent is mass conserved in the reactions of physics and chemistry.The question can be used to challenge students and develop their language and critical thinking skills.