Reactions in aqueous solutions are an important part of chemistry education. As experience shows, they are particularly difficult for students to understand. Hydrolysis is one such reaction. It occurs in organic and inorganic compounds with either covalent and ionic structures, but salt hydrolysis is a special example. Salt hydrolysis is complex, and to understand it, students must consider the reaction equilibrium, dissociation process, and acid-base properties of reactants and products. Additionally, in the upper-secondary-school curriculum, hydrolysis is described only qualitatively, which can lead students to misinterpret hydrolysis and solution equilibrium. In this study, 235 upper-secondary-school students answered questions about the acidity of common salt solutions and tried to justify their responses by writing appropriate chemical equations. An analysis of the answers revealed the students’ alternative conceptions and misconceptions. The character of the misconceptions showed that they are school-based and largely caused by excessive simplification of the process as well as the usage of inappropriate analogies. Key words: salt hydrolysis, acids and bases, alternative and misconceptions, chemical education research.

Inquiry-based teaching and learning methods are more and more widely used in the teaching natural sciences all over the world. The elements of inquiry are included in many national sciences’ core curricula and indicate that students should be actively involved in acquiring knowledge. This fact changes the teacher’s role in the classroom and the structure of everyday lessons. Independent inquiry helps students to develop various elements of scientific education, gain specific skills and competencies. Consequently, the assessment methods used so far are no longer sufficient and they should be expanded with new strategies, tools, and criteria. In recent years, there were many projects, in which teachers were trained in using both inquiry-based instructions and formative assessment. So far, unfortunately, there has been limited information on how teachers bring theory into practice and combine the new teaching and assessment methods, and how they adopt available teaching materials during everyday classes. This case study explored how experienced chemistry teachers, who have broad content, pedagogical content, and inquiry methodology knowledge, integrate inquiry-based teaching with formative assessment for the first time. The results of the study revealed the main limiting factors and teachers’ dilemmas.

The aim of this article is to present a hands-on laboratory experiment, which enables students to become acquainted with the idea and some principles of green chemistry in the context of the manufacture and use of lacquers. Environmental concerns, particularly the regulations concerning Volatile Organic Compounds have resulted in a dramatic change in the coating markets and traditional solvent-based (SB) technologies are being replaced by new, environmentally friendly processes based on ultraviolet (UV) or electron beam (EB) curing. In this exercise, the technological processes of SB and UV lacquers production and application were simplified and adapted for a school laboratory. The obtained lacquers are fully functional products with repeatable, easily measurable properties, which depend on the composition directly. The proposed method in this exercise is based on guided inquiry, however, it may be realized in a more or less open form, depending on the teacher’s goals, needs, and preferences.

The aim of this laboratory exercise is to present a high school hands-on laboratory experiment, focused on obtaining and investigating the properties of various polymorphic forms of aluminum oxide. Amphoterism plays a key role when discussing the law of periodicity and periodic changes of acid−base properties of elements and their compounds. In many school syllabuses, that issue is based on third period elements, so the amphoteric substances are aluminum, aluminum oxide, and aluminum hydroxide. Although demonstrating those properties for aluminum and aluminum hydroxide is relatively simple, the same reactions for alumina can be quite problematic. It is due to the fact that aluminum oxide exists in several polymorphic forms, and only one of them reacts with acids and bases. Moreover, the commercially available aluminum oxide materials are usually nonamphoteric. The exercise describes preparation of various polymorphic forms of aluminum oxide by thermal decomposition of aluminum hydroxide, and tests for its acid−base properties. The experiment can be used as a separate activity, or as a part of a larger scenario considering the properties of third period oxides. It was successfully conducted with over 100 high school (K−11) students studying chemistry at standard and higher level according to the International Baccalaureate Diploma Programme.

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