Volume 18, Issue 2  (2009)

Letters to the Editor:
M. Tsavkova Differenting Instruction Full text: PDF (65 K)	83
Curriculum Matters:
V.G. Ivanov, S.T. Ivanov Two-Body Problem Is Necessary and Important in Chemistry Full text: PDF (238 K)	86
42nd National Conference of the Bulgarian Teachers in Chemistry:
A. Tafrova-Grigorova, E. Boiadjieva, M. Kirova, A. Kuzmanov External Evaluation on Students' Achievements: Chemistry and Environment - 9th Grade Full text: PDF (493 K)	94
Bulgarian Educational Tradition:
V. Hadzhiliev Chemistry in Higher Medical Education Full text: PDF (153 K)	125
From the Research Laboratories:
G. Kumar Preparation, Coordination and Structure of Mixed Ligand Cobalt(II) Complexes of Histidine and Hippuric Acid Full text: PDF (170 K)	130
People in Chemistry:
D. Nedelchev Bulgarian Chemists: Eng.-chem. Nikola Nedelchev - Contractor, Teacher and Public Figure Full text: PDF (321 K)	137
History and Philosophy of Chemistry:
B.V. Toshev The Meteorite of Belogradchik Full text: PDF (693 K)	143
Archives:
B.V. Toshev Boris III About the University of Sofia (1939) Full text: PDF (136 K)	154
Guide for Authors:
Guide for Authors [In Bulgarian] Full text: PDF (112 K)	157
Guide for Authors [In English] Full text: PDF (41 K)	159
Khimiya, Volume 18, Issue 2 (2009) Khimiya. 18, 86- (2009) Author(s): V.G. Ivanov, S.T. Ivanov: Abstract.The objects and phenomena which are considered in chemistry (for example the hydrogen atom, diatomic molecule, the elastic collisions of diatomic molecules, etc.) lead to the solution of the two-body problem with electrical forces interaction. In this way the term "reduced mass" should be introduced as far as the motion of the both bodies transforms to the motion of one body with a reduced mass. The physical and mathematical peculiarities of the problem are underlined in the present paper. Keywords: centre-of-mass frame, two-body problem, reduced mass top Khimiya. 18, 94- (2009) Author(s): A. Tafrova-Grigorova, E. Boiadjieva, M. Kirova, A. Kuzmanov: Abstract.A study on the achievement of National Science Education Standards (compulsory level) in Chemistry and Environmental Protection school subject is being reported. The investigation has been carried out with 1189 9th formers from different type of secondary schools and a variety of regions in Bulgaria. The selection of the learning contents to be measured is made on the basis of content standards and corresponding programme of study, which serve as criteria of pupils’ achievements: what students are expected to know and are able to do at certain levels. The instrument of our study is a test, which is oriented to each of the expected attainment outcomes. Twelve experts judged whether the test adequately and representatively measured what it is intended to be measured. Results about the test validity and reliability, some statistical indicators, and difficulties of the test items and the whole test are presented. The students' achievements toward meeting the standards are found to be unsatisfactory for a great number of pupils, particularly for more than half of Secondary General School 9th-formers. The detailed analysis of the results of the external evaluation reveals a great deal of problems concerning chemistry school education in Bulgaria. Keywords: secondary education, chemistry education, educational standards, external evaluation, achievement test top Khimiya. 18, 125- (2009) Author(s): V. Hadzhiliev: Abstract.The paper argues for the importance of chemistry in the higher medical education. A short history of the chemistry textbooks for the medical departments of the Bulgarian medical education is presented. The contemporary challenges of the medical chemistry in the Medical universities in Bulgaria are listed and commented. Keywords: medical chemistry, textbooks, higher medical education top Khimiya. 18, 130- (2009) Author(s): G. Kumar: Abstract.Mixed ligand cobalt(II) complexes, Na2[Co(C6H5CONHCH2COO)(C6H8N3O2).H2O].9H2O and Na2[Co(C6H5CONHCH2COO)(C6H8N3O2).H2O].5H2O formed with histidine and hippuric acid have been synthesized. The mode of coordination and their structure have been determined by elemental analysis, spectral (Infra red and electronic spectra) studies and magneto-chemical measurements. Histidine shows a tridentate behaviour with coordinating through the carboxylate oxygen atom and the two nitrogen atoms of the imidazole and –NH2group. Hippuric acid acts as a bidentate ligand and the coordination occurs through the carboxylate oxygen and the nitrogen of the amido group. The remaining sixth coordination position is satisfied by a water molecule and hence the complexes have been suggested to show an octahedral structure. Keywords: Co(II) complexes, histidine, hippuric acid, preparation, structure top Khimiya. 18, 137- (2009) Author(s): D. Nedelchev: Abstract.Eng.-chem. Nikola Nedelchev graduated Chemistry from the Technical Higher School in Darmstadt. Later, in Bulgaria, he was a successful contractor, mainly in the field of chemistry. He developed a Laboratory “Rodhimind” in Karlovo for analysis and production of cosmetic and other chemical commercial goods. After the nationalization of his enterprise Nedelchev became a teacher in a professional school and his teacher career was successful and rewarded. Eng.-chem. Nedelchev participated actively in the Bulgarian tourist movement. Keywords: N. Nedeltscheff, Darmstadt, Karlovo, Rodhimind, tourism top Khimiya. 18, 143-0 (2009) Author(s): B.V. Toshev: Abstract.The paper reveals the history of the meteorite of Belogradchik (1874), samples of which have been presented in all over the world except Bulgaria. The meteorite, often named 'Virba', was studied and described by Daubree (1874) and Meunier (1893). Keywords: meteorites, Virba, Belogradchik, Daubree, Meunier top