amount of substance


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amount of substance

[ə′mau̇nt əv ′səb·stəns]
(chemistry)
A measure of the number of elementary entities present in a substance or system; usually measured in moles.
References in periodicals archive ?
A] exactly known, recent improvements in our knowledge of the values of the Rydberg constant, fine-structure constant, and relative atomic mass (formerly called "atomic weight") of the electron allow the molar mass of an entity X to be obtained with negligible increase in uncertainty from its own relative atomic mass, thereby facilitating the determination of the amount of substance of a sample of X (11).
This recommendation was well received by the CIPM, but because the unit was of a chemical nature, a further opinion was sought of the Consultative Committee for Amount of Substance (CCQM), in effect a committee on chemistry.
2] The recommendation included: (1) that only the liter should be used as the denominator in concentration units involving the volume of a mixture, and (2) that amount of substance, (base) unit mole, should be used whenever possible in reporting clinical laboratory results.
It consists of a plastic cassette with self-contained chemicals and a small plastic probe designed to pick up the right amount of substance to successfully run the test.
One of the key aspects of environmental safety of compounds is their toxicity, and another aspect is the amount of substance they leave behind in the environment which can potentially harm productive or useful organisms," he said.
This measurement was a key input needed to obtain an improved value for the Avogadro constant, a fundamental constant of nature related to the amount of substance, and which may one day lead to a new natural standard of mass.
The Tories' rhetoric is good and I'm glad to hear them talking about the North of England but I expect there isn't an enormous amount of substance behind it.
Full description of the subject of the contract and, accordingly, pharmaceuticals and medical devices included in the lots of the notice of initiation for the award of this contract is detailed in formulations, the amount of substance per unit and the estimated quantity attached documentation Technical Specifications (Appendix ?
In blood, heroin will generally stay for around 48- 72 hours depending on the amount of substance and how long ago was it taken," said PSM Chandran, reputed sports medicine doctor, who is also in the national antidoping disciplinary panel.
The post-match blast delivered by Stoke boss Tony Pulis about some of Chelsea's diving antics had a fair amount of substance too.
The aim is to develop children's understanding that a thinly spread out substance can be condensed into a pile, and whilst appearing smaller, is actually the same amount of substance.
The new system can inject a minute amount of substances into floating cells 200 times faster than the manual procedure.