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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°).
In thermodynamics, the enthalpy of sublimation, or heat of sublimation, is the heat required to sublimate (change from solid to gas) one mole of a substance at a given combination of temperature and pressure, usually standard temperature and pressure (STP). It is equal to the cohesive energy of the solid.
C 6 H 12 O 6: −1271 Isopropanol: Gas C 3 H 7 OH: −318.1 Methanol (methyl alcohol) Liquid CH 3 OH −238.4 Methanol (methyl alcohol) Gas CH 3 OH −201.0 Methyl linoleate Gas C 19 H 34 O 2: −356.3 Sucrose: Solid C 12 H 22 O 11: −2226.1 Trichloromethane Liquid CHCl 3: −134.47 Trichloromethane Gas CHCl 3: −103.18 Vinyl chloride: Solid ...
A typical phase diagram.The solid green line applies to most substances; the dashed green line gives the anomalous behavior of water. In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium. [1]
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 February 2025. Chemical element with atomic number 10 (Ne) This article is about the chemical element. For other uses, see Neon (disambiguation). Chemical element with atomic number 10 (Ne) Neon, 10 Ne Neon Appearance colorless gas exhibiting an orange-red glow when placed in an electric field ...
Gay-Lussac used the formula acquired from ΔV/V = αΔT to define the rate of expansion α for gases. For air, he found a relative expansion ΔV/V = 37.50% and obtained a value of α = 37.50%/100 °C = 1/266.66 °C which indicated that the value of absolute zero was approximately 266.66 °C below 0 °C. [ 12 ]
The number density (symbol: n or ρ N) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional linear number density.