The primary standard is a tape that is based upon the original master standard reference tape at NIST. Its amplitude at saturation is exactly 100% UR. Secondary standard reference cards are sold by PTB in Germany; these cards may be used to calibrate magnetic stripe analyzers.
A stable, high-purity material used in titrations and other chemical analyses to prepare solutions of precisely known concentration, or to determine the concentrations of substances which react with the primary standard material. For example, NaCl is a primary standard that can be used to determine the concentration of AgNO3 in a solution by titration: NaCl(aq) + AgNO3(aq) = AgCl(s) + NaNO3(aq).
a reagent that is extremely pure, stable, has no waters of hydration, and has a high molecular weight
a standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity
a substance which can be used for the direct preparation of a standard solution
"Primary ambient air quality standards" or "primary standards" mean levels established to protect the public health from adverse effects. The adverse effects that the standards should protect against include acute or chronic subjective symptoms and physiological changes that are likely to interfere with normal activity in healthy or sensitive individuals or to interfere unreasonably with the enjoyment of life or property. (From MN Rule 7009.0010)
A substance that is available in a stable and pure enough state to be made up directly into a standard solution.
standards set by EPA to establish limits to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly.
The standard reference units and physical constants maintained by the National Bureau of Standards upon which all measurement units in the United States are based.
Substances which are pure enough to be weighed out and dissolved in distlled water to give a solution of accurately known concentration. Less suitable substances are sometimes called secondary standards.
A substance of a known high degree of purity that undergoes one invariable reaction with the other reactant of interest.
This is a standard that is designated or widely acknowledged as having the highest metrological qualities in a specified field.
A pollution limit based on health effects. Primary standards are set for criteria air pollutants.
A primary standard in chemistry is a reliable, readily quantified substance. Features of a primary standard include: 1. High purity 2.
