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SCIENCE PROGRESS 



A SCHEMA OF A LOGICAL DIVISION OF CHEMISTRY 



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 (3 



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»— 1 



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/'I. Theoretical 

 Chemistry 

 (Doctrine of 

 cause) 



PURE CHEMISTRY 

 (Chemical force) 



PHYSICAL CHEMISTRY 



(Chemical force and physi 



cal energy) 



J 



II. Practical 

 Chemistry 

 (Doctrine of 

 appearance) 



III. Applied 

 Chemistry 

 (Doctrine of 

 effect) 



/IlA. 



IIb. 



OBJECTIVE 

 (Systematic description of 

 compounds) 



SUBJECTIVE 



(Composition of nature) 



/-IIlA. DIRECT 



(Direct application to 

 man's benefit) 



iiib. indirect 



( Indirect application to 

 man's benefits 



Stoichiometry (atom) 



Radiochemistry (electron) 



Stereochemistry (molecule) 



Mechanochemistry 



Thermochemistry 



Electrochemistry 



Photochemistry 



Inorganic Chemistry 

 Organic Chemistry 

 Analytical Chemistry 

 astrochemistry 

 Geochemistry 

 Biochemistry 



Sanitary Chemistry 

 Pharmaceutical Chemistry 

 Medical Chemistry 

 Nutritive Chemistry 

 Fermentation Chemistry 

 Agricultural Chemistry 

 Technical Chemistry 

 Industrial Chemistry 

 Commercial Chemistry 

 Engineering Chemistry 

 Manufacturing Chemistry 



Ia. Pure chemistry pertains to chemical force as far as this force can 

 arbitrarily be designated, and would therefore include : 



1. Stoichiometry, which investigates the amount of chemical force as 

 far as it expresses itself in the doctrine of definite or multiple proportions. 

 Under this heading comes atomic weight, valency, affinity, chemical equili- 

 brium due to concentration, and the speed of reactions caused by concen- 

 tration and not due to thermal, or electric causes. 



2. Radiochemistry, which takes up subatomic phenomena and studies 

 the laws of disintegration and transmutation. It deals with intrinsic 

 chemical force and the structure of the atom. It is the ultimate meeting 

 ground of physics and chemistry in which energy and matter appear to 

 become synonymous. 



3. Stereochemistry, which considers the spacial arrangement of the 

 atoms in the molecule. It includes not only the asymmetric atoms of C, S, 

 Se, Sn, Si, and the stereoisomers of N, Co, Pt, Cr, etc., but also the allotropic 

 forms of elements and the structure of crystals. 



Ib. Physical chemistry. — To this branch belong the phenomena resulting 

 from an interaction of chemical force and energy. Accordingly, the different 

 manifestations of energy may be termed mechanical, thermal, electrical, and 

 radiant energy. Hence there are : 



4. Mechanochemistry, dealing with the mechanical properties of sub- 

 stances : density, surface tension, pressure, compressibility, conductivity 

 of sound, mechanical strength and resistance. 



5. Thermochemistry treats of thermal phenomena associated with 

 chemical change (thermodynamics) and includes phenomena such as heat 

 of formation, heat of combustion, heat of neutralisation, as well as the 

 melting and boiling points, expansion by heat, conductivity of heat, etc. 



6. Electrochemistry considers the electrical and magnetical properties 

 of matter such as electro-motive force, ionisation, electro -affinity, magnetic 

 permeability, resistance, and conductivity. 



7. Photochemistry deals with light and its relation to substances and 

 chemical changes : e.g. photo-activity, luminescence, refraction and dis- 

 persion, absorption and colours, spectroscopy. 



