Tina Overton

Using a context-based approach to undergraduate chemistry teaching – a case study for introductory physical chemistry

This paper describes the rationale for using a context-based approach to the teaching of undergraduate physical chemistry, together with an overview of a case study, which has been developed to teach aspects of thermodynamics, kinetics and electrochemistry usually associated with the early stages of undergraduate chemistry courses. The context is that of the next generation of energy for an emerging city (Los Verdes) located in the south-west region of the USA. Working in groups, students use an array of physical chemistry principles to examine the combustion of fossil fuels and hydrogen, the use of hydrogen in fuel cells, solar power, and energy from a geothermal source. Students gain experience in working with both familiar and novel types of problem solving. [Chem. Educ. Res. Pract., 2005, 6 (3), 166-179]

Characterisation of Cr-silica polymerisation catalysts

The Cr–silica catalyst system is commercially important in the polymerisation of ethene. The nature of the chromium species present on the support following activation, as well as the nature of the polymerisation active oxidation state, have been investigated extensively but results have not always been conclusive. This investigation attempts to identify the nature of the surface species and the oxidation state of the chromium on both the activated and hydrogen-reduced samples. Temperature-programmed reduction was employed to identify the number of surface species on the support. These species were identified with the aid of EPR and UV–VIS diffuse reflectance spectroscopy.The surfaces of the activated Cr–silica catalysts were generally covered by chromate-like surface species, accompanied by dichromate-like species and chromium aggregates, the proportions of which were dependent upon chromium loading and activation conditions. These samples were mostly oxidised to CrVI during activation with traces of CrIII remaining after the treatment. Samples which were reduced in hydrogen indicated that reduction of CrVI to CrIII had occurred, but traces of CrVI always remained. The reduction process was accompanied by an increase in the amount of aggregation of the chromium.

Solving open-ended problems, and the influence of cognitive factors on student success

Problem solving is an essential skill for undergraduate chemists to acquire. Many problem solving activities encountered on undergraduate programmes are algorithmic, and require lower order cognitive skills to be applied in order to reach a solution. We have developed a number of open-ended problems that use a real life context and require the application of higher order cognitive skills. Students cognitive style has been determined and correlated with success in solving these problems. Early indications are that there is a correlation between field independence and problem solving ability.

Chemistry in sport: context-based e-learning in chemistry

This paper details the design and use of a learning resource for independent learning in chemistry. The course presents chemistry in the context of sport and draws upon a number of models of teaching and learning, including the Perry scheme of intellectual development, multiple intelligences (MI) theory, problem/context-based learning (P/CBL), mind mapping, case studies and web-based independent learning. The resource was produced as a website containing the context, content, and the tasks to be completed as part of the assessment. Hyperlinks to additional content and external web-pages were also included. The students’ response to the learning resource was positive; they enjoyed the course, found the context interesting and the presentation helpful. The assessment marks compared well with those from other modules taken by the same students in the same academic year. [Chem. Educ. Res. Pract., 2006, 7 (3), 195-202]

Information processing: a review of implications of Johnstone’s model for science education

The current review is concerned with an information processing model used in science education. The purpose is to summarise the current theoretical understanding, in published research, of a number of factors that are known to influence learning and achievement. These include field independence, working memory, long‐term memory, and the use of long‐term memory strategies. The implications of research for educational practice are discussed. It is recommended that educators consider models of information processing and adjust teaching practices accordingly.

A study of approaches to solving open-ended problems in chemistry

This paper describes the outcomes of a qualitative investigation into the range of different approaches that students use to solve open-ended, context rich problems. The study involved a small cohort of students individually solving open-ended, context-rich problems using a think aloud protocol. The problems required the students to develop a strategy, to identify data required and to make estimations. The problems did not lead to a single correct answer but rather a range of acceptable answers. Analysis of the transcripts and recordings of the sessions resulted in a limited number of categories of approaches to solving the problems. Applications of these approaches to individual students showed that there were three different types of problem-solver, described here as novice, expert and transitional. The results provide insight that will help tutors change how they, and subsequent students, approach problem solving.

Characterisation of modified Cr-silica catalysts

Abstract The Cr—silica catalyst system is commercially important in the polymerisation of ethene. This catalyst is made much more active by the inclusion of small quantities of titanium. This study attempts to identify the nature of any new species which may be formed by investigation of a series of titanium and magnesium modified Cr—silica catalysts. TPR experiments of the modified catalysts showed evidence for two new surface species. These species exhibited increased thermal stability with respect to the surface chromate and dichromate-like species already present and approximated to aggregates of titanium or magnesium chromate and dichromate.

Characterisation of Cr/silica catalysts. Part 2.—Ti- and Mg-modified catalysts

The Cr/silica catalyst system, which is commercially important in the polymerisation of ethane, is made much more active by the inclusion of small quantities of titanium. The nature of any new surface species which may be formed has been studied by investigation of a series of titanium- and magnesium-modified Cr/silica catalysts.Temperature-programmed reduction (TPR) experiments on the modified catalysts showed evidence for two new surface species. These species exhibited increased thermal stability with respect to the surface chromate and dichromate-like species already present and may approximate to aggregates of titanium or magnesium chromate and dichromate.

Investigation of the catalytic properties of the thermally activated dichloro-tetracarbonyl-tungsten in olefin metathesis reaction

Abstract Combined catalytic, preparative and spectroscopic studies revealed that the ring-opening metathesis polymerisation of norbornene initiated by thermally activated W(CO) 4 Cl 2 ( I ) proceeds mainly on the surface of a solid decomposition product formed in situ.

Critical thinking exercises for chemists Are they subject-specific?

Important thinking skills for professional chemists include ‘analysing and evaluating arguments’,‘making judgements’, ‘retrieving information’ and ‘experimenting’. A considerable literature provides evidence that these skills can be learned (and therefore taught).We have devised specific exercises to help students to develop these skills. Our exercises are grounded in chemistry and designed to be addressed by students working in groups in a classroom environment (sometimes in a computer classroom). The type of exercise and the classroom environment promote vigorous discussion which involves critical thinking and leads to effective learning. This article describes the exercises and argues that, while the specific examples are subject-specific, the approach used with all the types of exercise could be adapted to create subject-specific exercises for any discipline.