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The Green Book is a direct successor of the Manual of Symbols and Terminology for Physicochemical Quantities and Units, originally prepared for publication on behalf of IUPAC's Physical Chemistry Division by M. L. McGlashen in 1969. A full history of the Green Book's various editions is provided in the historical introduction to the third edition.
An MDL Molfile is a file format for holding information about the atoms, bonds, connectivity and coordinates of a molecule.. The molfile consists of some header information, the Connection Table (CT) containing atom info, then bond connections and types, followed by sections for more complex information.
Edexcel (also known since 2013 as Pearson Edexcel) [2] is a British multinational education and examination body formed in 1996 and wholly owned by Pearson plc since 2005. It is the only privately owned examination board in the United Kingdom. [3] Its name is a portmanteau term combining the words education and excellence.
The tiering of qualifications allows a subset of grades to be reached in a specific tier's paper. Formerly many subjects were tiered, but with the mid-2010s reform the number of tiered subjects reduced dramatically, including the removal of tiering from the GCSE English specifications. Untiered papers allow any grade to be achieved.
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and chemical formulas.The reactant entities are given on the left-hand side and the product entities are on the right-hand side with a plus sign between the entities in both the reactants and the products, and an arrow that points towards the products to show the direction of the reaction. [1]
Skeletal structural formula of Vitamin B 12. Many organic molecules are too complicated to be specified by a molecular formula. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. [1]
Chemical classification systems attempt to classify elements or compounds according to certain chemical functional or structural properties. Whereas the structural properties are largely intrinsic, functional properties and the derived classifications depend to a certain degree on the type of chemical interaction partners on which the function is exerted.
A chemical formula used for a series of compounds that differ from each other by a constant unit is called a general formula. It generates a homologous series of chemical formulae. For example, alcohols may be represented by the formula C n H 2n + 1 OH (n ≥ 1), giving the homologs methanol, ethanol, propanol for 1 ≤ n ≤ 3.