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Volume 24, Issue 2  (2015)

V. Simeonov
Academic Speech to the Graduate Students of the University of Sofia, Year 2014 [In Bulgarian]

Full text: PDF (784 K)

Letters to the Editor:
V. Simeonov
Intellectual "Synergy" between Two European Projects [In Bulgarian]

Full text: PDF (1508 K)

Curriculum Matters:
L. Nacheva-Skopalik, M. Koleva
Teaching Chemistry at Technical University

Full text: PDF (888 K)

Teaching Efficiency:
I. Kotseva, M. Gaydarova, G. Nencheva
Plickers Assisted Formative Peer Instruction Assessment [In Bulgarian]

Full text: PDF (1368 K)

P. A. Sarkodie, K. Adu-Gyamfi
Improving Students’ Performance in Naming and Writing Structural Formulae of Hydrocarbons Using the Ball-and-Stick Models

Full text: PDF (867 K)

M. E. A. Mohammed
Student Performance in a Seminar Based Examination of Basic Biochemistry Course

Full text: PDF (820 K)

J. Safarov, B. Ahmadov, S. Mirzayev, E. Hassel
Vapor Pressures of 1-Butanol over Wide Range of Temperatures

Full text: PDF (1228 K)

S. Ergül
Three Hypothetical Problems for Quantitative Precipitation

Full text: PDF (1031 K)

H. Petrova
Formation of a New Knowledge Through Graphical Modeling in Physics Education [In Bulgarian]

Full text: PDF (971 K)

Personalities in Science:
Z. Kostova
Professor Todor Georgiev Nikolov, A Geologist [In Bulgarian]

Full text: PDF (3143 K)

History and Philosophy of Science:
I. Kuleff
About the Creator of the Trace Atoms: 130 Years from the Birth of George de Hevesy [In Bulgarian]

Full text: PDF (1238 K)

New Information Media:
K. Yotovska
Design of University E-Learning Course (For Prospective Biology Teachers) [In Bulgarian]

Full text: PDF (1716 K)

B.V. Toshev
Cultural History of Science: New Ideas for the Matter and the Establishment of Modern Chemistry] (Fors, 2015) [In Bulgarian]

Full text: PDF (1525 K)


Khimiya, Volume 24, Issue 2(2015)

Khimiya. 24, 176-186 (2015) Author(s): L. Nacheva-Skopalik, M. Koleva:

Abstract.In the recent years, there have been several growing tendencies, which determine the increased necessity to educate adults. National Strategy for Continuing Professional Training has been developed. Priorities are given to further development of secondary and tertiary education with emphasis at quality of education and implementation of ICT. Tertiary education has its specific and important place in adult education and responsibility to provide high quality modern training conformed to the requirements of the labour market. Chemistry is one of the fundamental disciplines included in curricula for all students from the Faculty of Electrical Engineering and the Faculty of Mechanical Engineering at Technical University of Gabrovo. It is considered by students as an unintelligible and sophisticated science. Department of Chemistry faces some problems and challenges in order to compensate student’s insufficient entry level of knowledge, to enhance students' motivation in learning chemistry and to make it an attractive discipline. As a part of activities for improving efficiency of chemistry training an inquiry among students is held in order to evaluate their opinion and satisfaction with a teaching course. The applied approach gives qualitative and quantitative evaluation of the chosen quality criteria of the course. The results are used to make conclusions for improving the teaching course beginning with quality criteria with the biggest importance. It includes decision to develop and introductory e-learning course to achieve required starting level of knowledge. The measures taken contribute to enhanced efficiency and increased attractiveness of chemistry and enhanced students' motivation for learning chemistry.

Keywords: e-learning; decision making; evaluation of opinions; satisfaction measurement


Khimiya. 24, 187-202 (2015) Author(s): I. Kotseva, M. Gaydarova, G. Nencheva:

Abstract.The article presents the potential of Plickers - an up-to-date technology that has shown its effectiveness in the formative assessment of secondary school and university students. Shown are some of specifics of the interactive methods of formative peer instruction assessment on thee basis of which the authors select a well-grounded method of conducting empirical research in regard to Plickers. Partially added the tools of the study, presented also are the results from an inquiry held among students participating in the research as well as conclusions drawn through the analysis of the data base stored by Plickers.

Keywords: formative assessment, plickers, interactive methods, peer instruction


Khimiya. 24, 203-219 (2015) Author(s): P. A. Sarkodie, K. Adu-Gyamfi :

Abstract.Learning chemical concepts at the submicroscopic and symbolic levels has been identified as a difficult task for science students. Studies have shown that IUPAC nomenclature of organic compounds, which is at the symbolic level of learning chemical concepts, is a difficult concept when it comes to students’ learning. The current study involved a pre-service teacher and 60 high school students and investigated how students could improve upon their performance in naming and writing of structural formulae of hydrocarbons with the aid of ball-and-stick models. The pre-service teacher and the students were purposively selected to participate in the study. After seven weeks of teaching and learning of IUPAC naming and writing of structural formulae of hydrocarbons where the students physically manipulated the models, it was found that the students’ performance and attitude improved after the intervention. It is therefore recommended that science educators should continuously use already existing and newly developed models in teaching chemical concepts to help students to actively conceptualise such concepts at the symbolic level.

Keywords: hydrocarbons, structural formulae, students’ performance


Khimiya. 24, 220-225 (2015) Author(s): M. E. A. Mohammed :

Abstract.One of the major duties of any lecturer is to adopt different teaching methods in order to obtain excellent student performance. This study was conducted to investigate the performance of students in a seminar based examination compared to a lecture and practical sessions based examination. The basic course of biochemistry, taught to 35 students of chemistry and biology of the faculty of science at King Khalid University, was conducted following three teaching methods; lectures, practical sessions and seminar based teaching. Vitamins were taught through seminars prepared and presented by the students while the amino acids, protein and enzymes course was delivered through lectures and practical sessions. The final exam of the course included questions testing the knowledge of the students concerning the seminar and lecture based information. Regarding the results of the seminar based questions; 15 (42.9%) passed the exam and the range of the marks was (25- 90) while the students who passed the lecture and practical sessions based questions were 17 (48.6%) and the range of the marks was (35- 80). However, the pass mark was 60%. Although the highest marks were scored in the seminar based questions, the general performance of the students in the seminar based questions was poor compared to the lecture and practical sessions based questions.

Keywords: teaching methods, seminar-based, lecture-based


Khimiya. 24, 226-246 (2015) Author(s): J. Safarov, B. Ahmadov, S. Mirzayev, E. Hassel :

Abstract.Vapor pressure (VLE) of 1-butanol was studied at temperatures T=(274.15 K to 468.15) K using the two different static method installations. A glass cell was used below T = 323.15 K. Experimental uncertainties for the glass cell are ΔT = ±0.01 K and ΔP = ±(10 to 30) Pa (MKS Baratron pressure sensor). A metal cell was used in the range T = (323.15 to 468.15) K. Experimental uncertainty of temperature measurements for the metal cell is ΔT = ±0.01 K. Pressure was measured with two different 35 X HTC Omega-Keller pressure transmitters. Reproducibility of the vapor pressure measurements was ΔP = ±1.5 kPa for the pressures below P = 300 kPa and ΔP = ±5 kPa in the range P = (300 to 1000) kPa is. A fundamental literature analysis of 1-butanol has been done and experimental values were compared with the literature data. Observed deviation have been discussed. Measured values were fitted with the Antoine and Clausius-Clapeyron type equations. The best fit is that by Clausius-Clapeyron equation with four parameters.

Keywords: 1-butanol, vapor pressure, wide range of temperatures, Clausius-Clapeyron type equation


Khimiya. 24, 247-255 (2015) Author(s): S. Ergül :

Abstract.An analysis process involves the separation of the analyte from interferences. The precipitation can be used as a separation step when analyte is precipitated as an insoluble compound in a gravimetric analysis procedure. It must be determined the appropriate conditions such as the interval pH of solution, the volume and the interval of concentration of precipitating reagent for a successful quantitative precipitation procedure. In this context, the aim of this study is to model for the teaching of quantitative precipitation in analytical chemistry teaching how the stoichiometric calculations can be done to determine hypothetically the appropriate conditions for the quantitative precipitation. Three problems and their solutions are given for this aim. The appropriate conditions for the quantitative precipitation are also valid for the separability of analyte such as Fe3+ from interference such as Mn2+ by the precipitation procedure.

Keywords: quantitative precipitation, separation, separability, analyte, interference, precipitating reagent, interval of concentration, interval of pH.


Khimiya. 24, 256-263 (2015) Author(s): H. Petrova:

Abstract.The author offers a novel approach for the formation of new knowledge in physics education in secondary school. It is associated with the inclusion of graphical modeling of the physical laws, processes and phenomena. Such approach enriches the theory and practice of teaching physics with new ideas for building a system of student knowledge and skills for working with models, interpretation and logical thinking.

Keywords: education, physics, graphical modeling, knowledge


Khimiya. 24, 264-280 (2015) Author(s): Z. Kostova:

Abstract.The article traces briefly the life and work of Acad. Prof. Todor Georgiev Nikolov from his high school years to a world-class scientist. Deserved recognition is given to his research achievements in the field of geology, paleontology, evolution of the Earth, global environmental problems as well as to his teaching success in the education of students-geologists and geographers. Commented are his contributions as an organizer and leader of research institutions, national and international scientific forums. Reflected are his national and international awards.

Keywords: Prof. Todor Nikolov, geology, geography, evolution, scientific activity


Khimiya. 24, 281-293 (2015) Author(s): I. Kuleff:

Abstract.In the present paper was given the important facts in the life of George de Hevesy – the creator of radioactive isotopes in studying the metabolic processes of plants and animals. At the same time de Hevesy was discoverer of the hafnium, the neutron activation analyses, and alpha-emission of samarium. One of the lecturers with clear language by tracing chemicals in the body by replacing part of stable isotopes with small quantities of the radioactive isotopes.

Keywords: George de Hevesy, radiochemistry, tracers


Khimiya. 24, 294-305 (2015) Author(s): K. Yotovska:

Abstract.The concept of "design of e-learning course" in higher education has been the focus of various research communities during the last decade. Due to the growing number of publications on e-learning, the problem of model for university course becomes a widely discussed topic. The article presents the particular decision relating to the design of traditionally organized course in electronic course for pre-service biology teachers. Below is a description of the research procedure for theoretically grounded model design of pedagogical activity within the electronic university course, including its creation steps following the phases of the ADDIE model.

Keywords: e-learning, design, university course


Khimiya. 24, 306-312 (2015) Author(s): B.V. Toshev:

Abstract.During the seventeenth and eighteenth centuries, Europeans raised a number of questions about the nature of reality and found their answers to be different from those that had satisfied their forebears. They discounted tales of witches, trolls, magic, and miraculous transformations and instead began looking elsewhere to explain the world around them. In The Limits of Matter, Hjalmar Fors investigates how conceptions of matter changed during the Enlightenment and pins this important change in European culture to the formation of the modern discipline of chemistry [University of Chicago Press].

Keywords: basic concepts of science, matter, Sweden, European cultural tradition, modern chemistry


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