scholarly journals Classification of Chemical Substances using Particulate Representations of Matter: An analysis of student thinking

2007 ◽  
Vol 29 (7) ◽  
pp. 935-938 ◽  
Author(s):  
Marilyne Stains ◽  
Vicente Talanquer
Keyword(s):  
Student Thinking ◽  
Chemical Substances

scholarly journals CLASSIFICAÇÃO DAS SUBSTÂNCIAS QUÍMICAS: UM CONCEITO POUCO EXPLORADO NA EDUCAÇÃO QUÍMICA

Química Nova ◽  
2020 ◽  
Author(s):  
Cintia Lima ◽  
José Silva
Keyword(s):  
Teaching And Learning ◽  
Intellectual Development ◽  
Chemistry Teaching ◽  
Teaching Literature ◽  
Chemical Substances ◽  
Chemistry Students ◽  
Chemistry Textbooks ◽  
Chemical Concepts ◽  
History Of

The classification of chemical substances is a concept little explored in Chemistry teaching literature and in Chemistry textbooks at higher and secondary levels. The aim of this paper is to discuss theoretically the importance and contributions of this concept for teaching and learning Chemistry. The History of Chemistry reveals that the chemical criteria for classifying materials came up with the modern concepts of chemical element and chemical reaction, which gave rise to the notion of chemical similarity. Later, such similarity was related to molecular structure through functional groups. The classes of substances are related throughout chemical reactions, during which substances of given classes are transformed into substances of other classes, constituting a wide network. The classification of chemical substances can contribute to the intellectual development of Chemistry students, in order to study it, it becomes necessary to understand its theoretical foundation, as well as its characteristics of objectivity, completeness, simplicity and prediction. In this sense, one can contribute to the stimulation of perception, attention and abstraction t hat are typical of the chemical ways of thinking and communicating necessary for learning the chemical concepts linked to classification.

scholarly journals XXV.—On the Classification of Chemical Substances, by means of Generic Radicals

1866 ◽  
Vol 24 (2) ◽  
pp. 331-339 ◽  
Author(s):  
Alexander Crum Brown
Keyword(s):  
Chemical Structure ◽  
Chemical Substances ◽  
Double Decomposition ◽  
Natural Groups

The idea of chemical structure, as founded on that of atomicity (or the equivalence of atoms), enables us to divide any molecule, whose chemical structure is known, into radicals. The number of ways in which this may be done increases with the complexity of the molecule. Each of these modes of division corresponds to a series of conceivable reactions, some of which have been observed. Any one of these series may be made the basis of classification; but it is obviously most convenient to select for this purpose the most characteristic reactions, and those which are common to such substances as form natural groups. In studying these, we find that each series implies the presence of a particular radical, within which the reactions in question take place. We may call such series of reactions the Generic reactions, and the corresponding radicals Generic radicals. These are sometimes residues of double decomposition, but very frequently this is not the case, and this may account for the fact, that the importance of these generic radicals has been very much overlooked.

Chemometrics in Medicine and Pharmacy

2012 ◽  
Vol 11 (1) ◽  
pp. 11-26 ◽  
Author(s):  
Ján Mocák
Keyword(s):  
Drug Design ◽  
Clinical Diagnosis ◽  
Active Species ◽  
Biologically Active ◽  
Toxic Chemical ◽  
Chemical Substances ◽  
Effective Use ◽  
The University ◽  
Toxic Chemical Substances

Chemometrics in Medicine and PharmacyThis minireview summarizes the basic ways of application of chemometrics in medicine and pharmacy. It brings a collection of applications of chemometric used for the solution of diverse practical problems, e.g. exploitation of biologically active species, effective use of biomarkers, advancement of clinical diagnosis, monitoring of the patient's state and prediction of its perspectives, drug design or classification of toxic chemical substances. The aim of this contribution is a brief presentation of versatile potentialities of contemporary chemometrical techniques and relevant software. They are exemplified by typical cases from literature as well as by own research results of the Chemometrics group at Department of Chemistry, the University of Ss. Cyril & Methodius in Trnava.

scholarly journals I. The Bakerian Lecture. - Researches on vanadium

1868 ◽  
Vol 158 ◽  
pp. 1-27 ◽  
Keyword(s):  
Physical Properties ◽  
Crystalline Form ◽  
General Relationship ◽  
The Other ◽  
Lead Chloride ◽  
Hexagonal Prism ◽  
Vanadium Compounds ◽  
Chemical Substances ◽  
Lead Vanadate

Amongst the physical properties which point out the general relationship and classification of chemical substances, none has so deservedly obtained the confidence of chemists as isomorphism. The vanadium compounds have, however, proved a remarkable and unexplained exception to the conclusions which generally follow from well-ascertained identity of crystalline form. Rammelsberg, and afterwards, more completely, Schabus, pointed out the fact that the mineral vanadinite from several localities (a compound of lead vanadate and lead chloride) is isomorphous with apatite, pyromorphite, and mimetesite, minerals consisting of calcium phosphato-fluoride, lead phosphato-chloride, and lead arsenato-chloride, having the formulæ 3(Ca 3 P 2 O 8 ). Ca Fl 2 ; 3(Pb 3 P 2 O 8 ). Pb Cl 2 , and 3(Pb 3 As 2 O 8 ). Pb Cl 2 . The crystalline form of all these minerals is an hexagonal prism, terminated by 6-sided pyramids. The angle P: P (terminal) found by Rammelsberg for vanadinite, and by different observers for the other minerals, is as follows: (1) Vanadinite . 142° 30'; (3) Pyromorphite . 142° 15'; (2) Apatite . . 142° 2 0'; (4) Mimetesite . . 142° 7'; and the relation of the axes (1) 1:0·727; (3) 1:0·736; (2) 1:0·732; (4) 1:0·739.

scholarly journals Research in Adaptronic Automatic Control System and Biosensor System Modelling

2015 ◽  
Vol 8 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Vladimir Skopis ◽  
Igors Uteshevs
Keyword(s):  
Automatic Control ◽  
Adaptive Systems ◽  
Computer Experiments ◽  
The Other ◽  
System Modelling ◽  
Chemical Substances ◽  
Biosensor System ◽  
External Conditions ◽  
The One

Abstract This paper describes the research on adaptronic systems made by the author and offers to use biosensors that can be later inserted into the adaptronic systems. Adaptronic systems are based, on the one hand, on the adaptronic approach when the system is designed not to always meet the worst condition, but to change the structure of the system according to the external conditions. On the other hand, it is an extension of common automatic control ad adaptive systems. So, in the introduction firstly the adaptronic approach and biosensor as a term is explained. Adaptive systems, upon which adaptronic ones are based, are also mentioned. Then the construction of biosensor is described, as well as some information is given about the classification of biosensors and their main groups. Also it is suggested to use lichen indicators in industry to control concentration of chemical substances in the air. After that mathematical models and computer experiments for adaptronic system and biosensor analysis are given.

Classification, Chemistry, and Applications of Chemical Substances That Are Harmful to the Environment

2020 ◽  
pp. 20-49
Author(s):  
Sonika Jain ◽  
Pankaj Kumar Jain
Keyword(s):  
Pest Control ◽  
Plastic Waste ◽  
Hazardous Chemicals ◽  
Aquatic Life ◽  
Chemical Substances ◽  
Detailed Classification ◽  
Classification And Labeling ◽  
Harmful Effects ◽  
Chemical Class

A detailed classification of dyes has been discussed along with their chemical class and chemistry. International, regional, and national classification and labeling systems are already established and tested in practice. These hazardous chemicals can be liquid, solid, gas, aerosol, mists, vapors, semisolid, etc. Hazardous chemicals have wide applications (e.g., dyes, which are used for coloring purpose; pesticides, which are used for pest control; fertilizers are an essential part of the agriculture system; plastic and plastic waste; and e-waste to name a few). In this chapter, the authors deal with the identity, classification, and application of these harmful chemicals, especially dyes, which are mandatory to use. More emphasis is given to the natural and synthesized dyes about their use along with their modrants, which are a necessary part of the dyes without which they can't exhibit colors. Dyes have wide variety of applications, which have also been discussed along with their various harmful effects on environment, mankind, and aquatic life.

scholarly journals 2. On the Classification of Chemical Substances by Means of Generic Radicals

1866 ◽  
Vol 5 ◽  
pp. 561-562
Author(s):  
Alexander Crum Brown
Keyword(s):  
Chemical Substances

In this paper the author proposes to use for purposes of classification those radicals or parts of molecules which are common to genera of substances, and within which the changes characteristic of these genera take place.

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