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Standards are used in analytical chemistry. Here, a primary standard is typically a reagent which can be weighed easily, and which is so pure that its weight is truly representative of the number of moles of substance contained. Features of a primary standard include: High purity; Stability (low reactivity)
A standard solution created from a secondary standard cannot have its concentration accurately known without stoichiometric analysis against a primary standard. An example of a secondary standard is sodium hydroxide , a hydroscopic compound that is highly reactive with its surroundings.
Reagent Chemicals [a] is a publication of the American Chemical Society (ACS) Committee on Analytical Reagents, [1] detailing standards of purity for over four hundred of the most widely used chemicals in laboratory analyses and chemical research. Chemicals that meet this standard may be sold as "ACS Reagent Grade" materials.
Tris is also used as a primary standard to standardize acid solutions for chemical analysis. Tris is used to increase permeability of cell membranes. [ 13 ] It is a component of the Moderna COVID-19 vaccine [ 14 ] and the Pfizer-BioNTech COVID-19 vaccine for use in children 5 through 11 years of age.
[4] [5] [6] It is also used as a primary standard for calibrating pH meters because, besides the properties just mentioned, its pH in solution is very stable. It also serves as a thermal standard in thermogravimetric analysis. [7] KHP dissociates completely in water, giving the potassium cation (K +) and hydrogen phthalate anion (HP − or ...
the central organic synthesis reagent for hydroboration Dicyclohexylcarbodiimide: an organic compound; primary use is to couple amino acids during artificial peptide synthesis Diethyl azodicarboxylate: a valuable reagent but also quite dangerous and explodes upon heating Diethyl ether: organic compound; a common laboratory solvent Dihydropyran
In chemistry, a reagent (/ r i ˈ eɪ dʒ ən t / ree-AY-jənt) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. [1] The terms reactant and reagent are often used interchangeably, but reactant specifies a substance consumed in the course of a chemical reaction. [ 1 ]
Secondary reference standards: Reference standards calibrated against and traceable to primary WHO materials and intended for use in routine tests; Reference reagent: a WHO reference standard, the activity of which is defined by WHO in terms of a unit; For chemical substances some pharmacopoeias [10] use the WHO terms [11]