Сп. „Химия“, книжка 3/2019

Education: Theory & Practice

Principles of the Career Development of the Young Scientist [In Bulgarian}

Резюме. The results of three questionnaires for the participants of the Second School within the frames of the European operational program “Science and education for intelligent growth” are discussed in the present paper. The goal of the questions asked is to achieve an objective assessment about the different modules of the School – information, project activity and role of publication for career development. The data obtained were treated and interpreted by the use of multivariate statistical methods (hierarchical and non-hierarchical analysis) which made it possible to reveal hidden interactions both between the evaluations given and the attitude of the participants to the objectives of the School. Important conclusions for the role of the scientific project activity and publication activity with respect to age, interests and career level of the participants were drawn.
Keywords: training school; European operational program; questionnaires; cluster analysis

I. Pancheva, M. Nedyalkova, S. Kirilova, P. Petkov, V. Simeonov

Education: Theory & Practice

Methodological Approach for Identifying Talanted Students in Science Through Lean Piaget’s Phenomena and Binet-Terman’s IQ Test [In Bulgarian]

Резюме. The paper presents a correlation model based on Piaget’s phenomena and Binet-Terman’s intelligence test. This approach provides the opportunity for assessing the mental age through conducting Jean Piaget’s experiments as well as vice versa – through determining Piaget’s stage the IQ can be specified. The suggested model would allow the mainstream teacher as well as the team of experts assisting personality development in the school, to easily orientate in the abilities a student with special educational needs has and to design his/her individual programs so that they would correspond to his/her development.
Keywords: gifted students, Piagetian inventories, intelligence quotient, Stanford–Binet intelligence sales

M. Zamfirov

New Approaches

Teaching Acrivities and Activity Coefficients: An Alternative Approach

Резюме. The article outlines an approach to teaching the concept of activity and activity coefficients starting with the relationship between Gibbs free energy change and pressures of ideal gases for the process of their mixing. The gases are then assumed to be the vapor in equilibrium with a liquid solution, allowing concentrations in the solution to be related to the vapor pressures through Raoult’s or Henry’s laws, appropriately modified to account for any deviation from these laws. Chemical potentials of individual components of the liquid solution are then related to activities, and the expression for the equilibrium constant in terms of activities is developed.
Keywords: activity; activity coefficient; equilibrium constant; Raoult’s law, Henry’s law; chemical potential

J. Ahmad

Curriculum Matters

High-School Students’ Misconceptions About Chemical Equilibrium [In Bulgarian]

Резюме. Chemical equilibrium is one of the most important and difficult topics in а high-school chemistry curriculum. The determination of the nature of students’ misconceptions (alternative conceptions) related to this topic, their detection and identification are important for both Science Education theory and its practical application. The purpose of the present research is to identify misconceptions about chemical equilibrium of Bulgarian high-school students who study a subject Chemistry and Environmental protection at an advanced level. A diagnostic test consisting of 21 questions was used as a main tool, in which most of the questions were two-tire. A semi-structured interview with students was also used as a support tool for the research. The final version of the test had been validated by experts. The reliability of the test is 0,8. A total of 400 students (N = 400) aged 17 – 19 took the test, of which 226 girls and 174 boys. In 34% of high-school students were identified 16 misconceptions related to chemical equilibrium, which were grouped in 6 areas: definition and establishment of chemical equilibrium; changes in equilibrium conditions; heterogeneous equilibrium; catalyst function; equilibrium constant expression; confusion of kinetics and chemical thermodynamics.
Keywords: misconceptions; alternative conceptions; chemical equilibrium; learning problems; high-school students

K. Atanassov, A. Gendjova

Teaching Efficiency

Using More Real Life Examples for Enhance Learning in a General Chemistry Lecture

Резюме. Below are a few more “real life” examples that have been continually used successfully over the years to help students remember and understand some of the concepts taught in general chemistry. These examples try to reinforce the chemical ideas as well as provide a way for students to remember these ideas. They are taught with the idea of having fun and trying to relate experiences that the students may have had or heard about while learning chemistry on a given topic.
Keywords: chemistry education, lecture, examples

A. E. Burns

Experiments

Utilisation of the Static Evans Method to Measure Magnetic Susceptibilities of Transition Metal Acetylacetonate Complexes as Part of an Undergraduate Inorganic Laboratory Class

Резюме. The Evans method is routinely utilised to collect paramagnetic susceptibility data via the employment of relevant Nuclear Magnetic Resonance (NMR) methods. As the sample is normally spun, the lack of such a function on benchtop NMR instrumentation required a “static” approach to be employed. We have utilised the static Evans method approach to measure the magnetic susceptibilities, and subsequently the effective magnetic moment, of a series of synthesised transition metal acetylacetonate complexes in order to appraise the d-electron configuration. The obtained values were compared to those obtained using a Guoy balance and theoretical calculations. The collection of T1 relaxation data further exemplifies the effect of the paramagnetic centre in terms of aiding relaxation, and therefore links to Magnetic Resonance Imaging (MRI) contrast agents, thus providing students with real-world perspective of the experiment conducted.

Keywords: benchtop-NMR; Evans method; transition metal chemistry

A. Dobzhenetskiy, C.A. Gater, A.T.M. Wilcock, S.K. Langley, R.M. Brignall, D.C. Williamson, R.E. Mewis

Problems

Study of Moroccan Pupils’ Skills in Solving Chemistry Problems at First Year of High-School

Резюме. This study purpose to analyze the macro-skills (assimilate, analyze, and achieve) that Moroccan pupils (16-17 years) of high-school (first-year classes) master to solve chemistry problems involving chemical concepts such as equation of reaction, complete reaction, molar mass, amount, volume, concentration, RICE table, and dilution. The pupils were asked to provide answers on problems’ questions including implicit tasks, which are arranged from the simple to the complexe at the problems’ end. The pupils’ answers are analyzed in terms of macro-skills with regard to the (1st, 2nd, 3rd degree) skills, which pupils would master to succeed the different tasks relevant for the problems, and discussed in terms of novice/expert problems solvers taking considering conceptual understanding and algorithms that pupils could master to solve correctly the problems’ tasks. The findings show that pupils succeed tasks, which require mastering of assimilate skills (1st degree skills) more easily than those requiring others skills, especially achieve skills (3rd degree skills), needed to solve the complexe tasks.
Keywords: problem-solving; tasks; knowledge; skills; assimilate; analyse; achieve; performance; capacity

A. Ouasri

From the Research Laboratories

Estimation of Genotoxic Effect of Insecticide Chromagor at Goldfish (Carassius auratus) after 5 Days of Treatment

Резюме. The genotoxic effects of insecticide chromagor(dimethoate) were evaluated in goldfish Carassius auratus using the micronucleus test. The aim of this study is to estimate the damage of DNA , after treatment of goldfish Carassius auratus for five days with insecticide chromagor. The micronucleus assays have been used increasingly to evaluate genotoxicity of many compounds in polluted aquatic ecossystems. In order to investigate the frequencies of micronuclei and to assess the sensitivity of species, the results were compared with samples taken at the reference site and maintained in the laboratory, and fish treated with insecticide chromagor. Our results show significant increase of number of micronuclei in erythrocytes of goldfish.

Keywords: insecticide, chromagor, DNA, fish

K. Kurteshi, Z. Shaqiri

From the Research Laboratories

Bioaccumulation of Cadmium in Edible Wild Mushroom (Suillus luteus), Bulgaria

Резюме. The study was conducted on Cambisols soils and wild edible mushroom (Suillus Luteus) from the Batak Mountain, Bulgaria. The total cadmium content in the soils was measured after their decomposition with HCl and HNO3 acids. The mushroom samples were prepared by dry ashing and subsequent dissolution in HCl. The cadmium levels were determined by PerkinElmer AAnalyst 800 model atomic absorption spectrometer (PerkinElmer Instruments, Shelton, CT, USA) equipped with transversely heated graphite atomization (THGA), and a longitudinal Zeeman effect background corrector was also used. A correlation/regression analysis was carried out to reveal possible associations between pH, humus content, and total cadmium content of the soils and the concentration of this element in the mushroom samples. It was calculated BF = 0.38. BF < 1 indicates that the fungus is a metal ion bioreactor.
Keywords: cadmium, Suillus Luteus, Bulgaria

P. Papazov, P. Denev

History and Philosophy of Science

The 100th Anniversary of IUPAC as an International Human Rights Organization for Chemists in 2019: Statute, Structure and Competence

Резюме. IUPAC 100th anniversary will be celebrated in 2019 year all over the world by the chemistry community predominantly, like a globally-recognized authority on chemical nomenclature and terminology. In the view of the fact that this honoring is commemorated only once in time, the present announce reveals briefly how this organization works, its statue, structure and competence. The principal goal is to synopsize the overall mission of this so much acknowledged international union historically during one century under the key idea of creating a common language for chemistry and its long lasting impact.
Keywords: 100th anniversary, IUPAC, mission, structure, competence.

M. Atanassova, R. Angelov

Reviews

A Tale of Seven Scientits (Scerri, 2016)

S. Kirilova

Свързани статии:

Сп. „Химия“, книжка 2/2019 Сп. „Химия“, книжка 4/2019 Сп. „Химия“, книжка 5/2019 Сп. „Химия“, книжка 6/2019