Chemistry conceptual problems

Dobbs, Betty Jo Teeter. "Conceptual problems in Newton s early chemistry a preliminary study." In Religion, science and worldview, eds. Margaret J. Osier and Paul Lawrence Farber, 3-32. Cambridge Cambridge Univ P, 1985. 

The conceptual problems start when considering materials such as plutonium, which is a by-product of the nuclear electricity industry. Plutonium is one of the most chemically toxic materials known to humanity, and it is also radioactive. The half-life of 238Pu is so long at 4.5 x 108 years (see Table 8.2) that we say with some certainty that effectively none of it will disappear from the environment by radioactive decay and if none of it decays, then it cannot have emitted ionizing a and f) particles, etc. and, therefore, cannot really be said to be a radioactive hazard. Unfortunately, the long half-life also means that the 238Pu remains more-or-less for ever to pollute the environment with its lethal chemistry. 

Then, we focused on conceptual problems such as the definition of local spins that do hardly emerge naturally in holistic quantum theory. The local spin concept was rigorously introduced in quantum chemistry about 10 years ago by Clark and Davidson. We reviewed the most important contributions in this field and... 

We hope the reader has been convinced that it is technically feasible to describe a photochemical reaction coordinate, from energy absorption to photoproduct formation, by means of methods that are available in standard quantum chemistry packages such as Gaussian (e.g., OPT = Conical). The conceptual problems that need to be understood in order to apply quantum chemistry to photochemistry problems relate mainly to the characterization of the conical intersection funnel. We hope that the theoretical discussion of these problems and the examples given in the last section can provide the information necessary for the reader to attempt such computations. 

Moreover, the original concept of an integer number that quantified oxidation has remained the cornerstone of "inorganic chemistry" nomenclature — at least as it is practiced by IUPAC. [10] This is notwithstanding the fact that conceptual problems are attenuated when the familiar oxidation numbers that "work" for one compound (or ion) are used to determine the oxidation number of other compounds. 

Despite the fact that the solvent is an important factor in determining the properties of molecules in solution, it should be realised that moving to the gas phase does not solve all the conceptual problems of physical organic chemistry. We will consider this for the rest of this chapter. 

One of the great rewards of studying chemistry is to become a good problem solver. Being able to solve complex problems is a talent that will serve you well in all walks of life. It is our purpose in this text to help you learn to solve problems in a flexible, creative way based on understanding the fundamental ideas of chemistry. We call this approach conceptual problem solving. 

Students in the treatment group did better than those in a traditional course on both a chemistry conceptual test and a chemistry problem-solving test. Nob and Scharmann agreed with authors of the literature on conceptual understanding who argue that the ability to solve numerical problems doesn t imply conceptual understanding. But they also questioned the assumption that the ability to solve pictorial problems necessarily implies conceptual understanding. 

Phelps (1996) studied an intervention based on an emphasis on conceptual problem-solving. Much of the power of her study results from the fact that she implemented this technique in both a general chemistry course for science majors and a course for nursing and liberal arts students. Many of the same tasks were used in both courses. The very different responses these tasks elicited from the two groups of students were striking. Throughout the semester, the science majors were less willing to interact and ponder the problem at hand. 

Mason, D.S., Shell, D.E. Crawley, E.E. (1997). Differences in problem-solving by nonscience majors in introductory chemistry on paired algorithmic-conceptual problems. Journal of Research in Science Teaching, 34, 905-924. 

To explain these conceptual problems, Bergquist Heikkinen (1990) have suggested that these are related to the content of chemistry courses. As discussed in the previous subsection, the concepts of reversible reactions and chemical equilibrium are at odds with conceptions of chemical reactions which are normally discussed earlier in the syllabus (see Table 1). 

Students often have problems handling the mathematical steps which are necessary to solve equilibrium calculations (Huddle Pillay, 1996). The authors, who studied first-year students of chemistry in South Africa, suggest that these problems are related to students conceptual problems with the abstract concept of chemical equilibrium. 

When applied to secondary and tertiary chemistry teachers, both the amount of subject matter knowledge and experience of teaching the content contribute to better recall and conceptual understanding. Gorin (1994) reported that teachers and students had difficulty understanding that the number of. particles is the same in one mole of every substance. Their conceptual problem was caused probably by the lack of a context for the mole. Lin, Cheng, Lawrenz (2000) concluded that both students and teachers in Taiwan had difficulty applying gas laws (e.g., Boyle s and Charles s) in practical situations. 

Quantum mechanics is cast in a language that is not familiar to most students of chemistry who are examining the subject for the first time. Its mathematical content and how it relates to experimental measurements both require a great deal of effort to master. With these thoughts in mind, the authors have organized this introductory section in a manner that first provides the student with a brief introduction to the two primary constructs of quantum mechanics, operators and wavefunctions that obey a Schrodinger equation, then demonstrates the application of these constructs to several chemically relevant model problems, and finally returns to examine in more detail the conceptual structure of quantum mechanics. 

The polymer-supported catalysts are thus important conceptually in linking catalysis in solutions and catalysis on supports. The acid—base chemistry is fundamentally the same whether the catalytic groups are present in a solution or anchored to the support. The polymer-supported catalysts have replaced acid solutions in numerous processes because they minimise the corrosion, separation, and disposal problems posed by mineral acids. 

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