Symbols and Formulas

These have nothing in common with algebraical s bols and formulae. They are mere abbreviations, and are intended to express only the arithmetical operations of addition and subtraction. Various systems have been given to the world but that which has finally obtained the most extensive currency among the chemists of the day, is one proposed by Liebig and Poggen-dorif, which we now proceed to explain. 

The symbol of an element, standing alone, signifies 1 atom, or equivalent, of the element. Thus O stands for 1 atom of oxygen, H for 1 atom of hydrogen, and Fe for 1 atom of iron (femim). 

A symbol, with a small figure below and to the right, signifies as many atoms of the element as the figure expresses. Thus O, means 2 atoms of oxygen, S, 5 atoms of sulphur. 

Two symbols joined by the sign or simply placed together, signify a compound of 1 atom of each element. Thus, H -1- 0, or simply H O, means water, a compound of 1 atom hydrogen, and 1 atom oxygen. 

If a figure be attached, as above, to either or both symbols, it multiplies that symbol only to which it is attached. Thus Mn 0, is the symbol for peroxide of manganese, a compound of 

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Further steps toward universality are taken by the replacement of element and compound names wherever possible by symbols and formulas, and by adding to data in older units their recalculated SI equivalents. The usefulness of the reference sections has been increased by giving journal-title abbreviations according to the Chemical Abstracts Service Source Index, by listing in each reference all of its authors and by accompanying references to patents and journals that may be difficult to access by their Chemical... 

It is recommended (REC. 38) that the wave number or frequency of any spectroscopic transition be expressed (corresponding to RECS. 29-31 for term symbols and formulas) in the general form... 

Write a balanced equation for each of the following reactions, substituting symbols and formulas for names. Include the state of each reactant and product. Then identify the reaction type for each. If more than one reaction type applies, list all that apply. 

Besides, Dalton proposed new symbols for chemical elements, as well as a new way of graphic representation of compounds. Some of the symbols and formulas taken from his treatise A New System of Chemical Philosophy (1808) are shown in Fig. 43. Note that Dalton sought... 

Symbols and formulas have a deeper significance, which will be considered as the necessary facts accumulate. 

Chemical Equations. — The mathematical significance of symbols and formulas, together with the conception of the conservation of matter, allows reactions to be represented quantitatively by equations. Chemical equations differ from algebraic equations in one vital respect they are the result of experiment. Thus in Exp. 15 it was shown that magnesium unites with oxygen to form magnesium... 

Notation, n. The written language of chemistry, especially the symbols and formulas. 

Chemical symbols and formulae have been frequently used in place of names to save space and often to secure clarity. Where an arrow (->) from the donor atom appears, it does not imply that the bond is different from the rest. 

One who reads widely in the patents of many countries soon acquires the feeling that patents, as means of exchanging information of progress between countries, stimulate international comity and understanding. This is particularly true of chemical patents which, like music and mathematics, are blessed with symbols and formulas that know no boundaries. 

Chemical equations are used to represent reactions. They are written using symbols and formulas for elements and compounds. Once the symbols and formulas are written, the equation can be balanced only by changing coefficients. 

The most important subjects of 15 lectures in chemistry education can be presented in a kind of pie-chart (see Fig. 0.1) Learners ideas and misconceptions experiments structural and mental models terminology, symbols and formulae every-day-life chemistry media motivation teaching aims [1]. Because we want to put a lot of emphasis on the learner, she or he is therefore placed at the centre of the diagram. Secondly, scientific ideas should be reflected in association with appropriate teaching processes for the learner. Finally there should be reflections on the human element or context to each subject as Mahaffy [2] has proposed. There are free sectors in that diagram - for more chemistry education subjects to reflect upon. In this book emphasis is given to students preconceptions and misconceptions experiments structural and mental models terminology, symbols and formulae. 

Chemical equations can be given as word equations, which use the names of the reactants and products, or they can be written as formula equations, which use symbols and formulas of the species involved. The reaction of calcium oxide (agricultural lime) with water to form calcium hydroxide is written here as a word equation. 

In the cryptic expression and symbolic representation which characterised alchemy and found a later expression in the symbols and formulae of modern chemistry, sophic sulphur and sophic mercury assumed a bewildering variety of forms. For example, they were known as Osiris and Isis, sun and moon, Sol and Luna, brother and sister, masculine and feminine, active and passive, giver and receiver, seal and wax, fixed and volatile, wingless lion and winged lioness, lion and eagle, and so forth. The Stone, when conceived as the result of the union of masculine and feminine principles, was sometimes represented as an infant. 

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