Chemical change secondary education

Nowadays, a kinetic derivation of the Law of Mass Action is usually not included in chemistry textbooks. Instead, a qualitative introduction of chemical equilibrium, which uses kinetic ideas, has become quite common in many textbooks ( dynamic equilibrium ) for secondary education (age of students 14-16 years). The stabihty of chemical equilibrium and the ways these equilibria respond to external changes are usually addressed next. In this respect, much attention traditionally is paid to Le Chatelier sprinciple. This principle has been, and is still, used extensively to explain or predict the behaviour of a chemical system at equilibrium due to changes in pressure, volume, concentrations, or temperature. This is done in terms of changes in the concentrations of reactants and products followed by the establishment of a new state of equilibrium. This principle was applied to various examples... 

After the introduction of the concept of chemical equilibrium it is common to address the stability of chemical equilibrium, that is, the disturbance and subsequent re-establishment of a state of equilibrium within a chemical system. In upper secondary education (students age 16-18 years), changes in chemical equilibrium are usually studied from a semi-quantitative perspective, which in many countries is still dominated by the use of Le Chateher s principle. Although many variations of this principle exist, a common formulation is When a stress is applied to a system, the system responds in a way to try to relieve the stress. 

Many teachers will state that their students have problems understanding thermodynamics. It is our impression that the same apphes to some secondary school teachers themselves. It is remarkable that so little research has been done on this aspect of chemical education, compared with subjects like chemical change, chemical calculations, or equilibrium. 

The papers in this book thus shed light on a multitude of responses to the periodic system. The smallness of the chemical community, for example, played a role in the Scandinavian countries reaction to the system. Consequently, even among chemists who had a practical orientation and who did not pay much attention to theory in general, one particular researcher with an interest in theory—such as Julius Thomsen, a pioneer of thermochemistry in Denmark—could change the situation. Thomsen offered a neo-Proutean speculation of internally structured atoms, which Mendeleev denied, but his ideas inspired Niels Bohr s development of anatomic theory in 1913. In Norway, by contrast, one chemistry textbook that happened to deny the periodic system and that was dominant in secondary education, delayed the system s reception there until as late as 1970. 

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