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In chemistry a donor number (DN) is a quantitative measure of Lewis basicity.A donor number is defined as the negative enthalpy value for the 1:1 adduct formation between a Lewis base and the standard Lewis acid SbCl 5 (antimony pentachloride), in dilute solution in the noncoordinating solvent 1,2-dichloroethane with a zero DN.
A brass test cup is filled with a test specimen and closed with a lid, through which an ignition source can be introduced periodically. The sample is heated and stirred at specified rates depending on the material that is being tested.
In chemistry, a chemical test is a qualitative or quantitative procedure designed to identify, quantify, or characterise a chemical compound or chemical group. Purposes
[1] [2] Some of the commonly used grades of purity include: ACS grade is the highest level of purity, and meets the standards set by the American Chemical Society (ACS). The official descriptions of the ACS levels of purity is documented in the Reagent Chemicals publication, issued by the ACS.
Theoretical chemistry requires quantities from core physics, such as time, volume, temperature, and pressure.But the highly quantitative nature of physical chemistry, in a more specialized way than core physics, uses molar amounts of substance rather than simply counting numbers; this leads to the specialized definitions in this article.
For example, the indirect Coombs test detects the presence of anti-Rh antibodies in a pregnant woman's blood serum. A patient might be reported to have an "indirect Coombs titer" of 16. This means that the patient's serum gives a positive indirect Coombs test at any dilution down to 1/16 (1 part serum to 15 parts diluent).
Chemical specificity is the ability of binding site of a macromolecule (such as a protein) to bind specific ligands. The fewer ligands a protein can bind, the greater its specificity. Specificity describes the strength of binding between a given protein and ligand.
In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure , a substance with high volatility is more likely to exist as a vapour , while a substance with low volatility is more likely to be a liquid or solid .