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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. The concentration of a standard solution made with sodium ...
A primary standard in metrology is a standard that is sufficiently accurate such that it is not calibrated by or subordinate to other standards. Primary standards are defined via other quantities like length, mass and time. Primary standards are used to calibrate other standards referred to as working standards. [1] [2] See Hierarchy of Standards.
An example of a primary standard was the international prototype of the kilogram (IPK) which was the master kilogram and the primary mass standard for the International System of Units (SI). The IPK is a one kilogram mass of a platinum-iridium alloy maintained by the International Bureau of Weights and Measures (BIPM) in Sèvres, France.
A burette and Erlenmeyer flask (conical flask) being used for an acid–base titration.. Titration (also known as titrimetry [1] and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed).
There are three levels of standards in the hierarchy of metrology: primary, secondary, and working standards. [20] Primary standards (the highest quality) do not reference any other standards. Secondary standards are calibrated with reference to a primary standard. Working standards, used to calibrate (or check) measuring instruments or other ...
ISO 186:2002 Paper and board — Sampling to determine average quality; ISO 187:1990 Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples; ISO 188:2011 Rubber, vulcanized or thermoplastic — Accelerated ageing and heat resistance tests
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]
For example: HCl + NaOH → NaCl + H 2 O. Acidimetry is the specialized analytical use of acid-base titration to determine the concentration of a basic (alkaline) substance using standard acid. This can be used for weak bases and strong bases. [8] An example of an acidimetric titration involving a strong base is as follows: Ba(OH) 2 + 2 H + → ...