Search results
Results from the WOW.Com Content Network
In chemistry, IUPAC changed its definition of standard temperature and pressure in 1982: [1] [2] Until 1982, STP was defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 1 atm (101.325 kPa).
The standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions.A degree sign (°) or a superscript Plimsoll symbol (⦵) is used to designate a thermodynamic quantity in the standard state, such as change in enthalpy (ΔH°), change in entropy (ΔS°), or change in Gibbs free energy (ΔG°).
The second table gives the most stable structure of each element at its melting point. (H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, and Rn are gases at STP; Br and Hg are liquids at STP.) Note that helium does not have a melting point at atmospheric pressure, but it adopts a magnesium-type hexagonal close-packed structure under high pressure.
STP was first synthesized and tested in 1963 by Alexander Shulgin, who was investigating the effect of 4-position substitutions on psychedelic amphetamines. [3]In mid-1967, tablets containing 20 mg (later 10 mg) of STP were widely distributed in the Haight-Ashbury District of San Francisco under the name of STP, having been manufactured by underground chemists Owsley Stanley and Tim Scully.
This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter , as well as the changes it undergoes during chemical reactions ...
Sodium triphosphate (STP), also sodium tripolyphosphate (STPP), or tripolyphosphate (TPP), [1]) is an inorganic compound with formula Na 5 P 3 O 10. It is the sodium salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid. It is produced on a large scale as a component of many domestic and industrial products ...
The standard molar entropy of a gas at STP includes contributions from: [2] The heat capacity of one mole of the solid from 0 K to the melting point (including heat absorbed in any changes between different crystal structures). The latent heat of fusion of the solid. The heat capacity of the liquid from the melting point to the boiling point.
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 .