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All values refer to 25 °C and to the thermodynamically stable standard state at that temperature unless noted. Values from CRC refer to "100 kPa (1 bar or 0.987 standard atmospheres)". Lange indirectly defines the values to be standard atmosphere of "1 atm (101325 Pa)", although citing the same NBS and JANAF sources among others.
Steinhart–Hart equation. The Steinhart–Hart equation is a model relating the varying electrical resistance of a semiconductor to its varying temperatures. The equation is. where. T {\displaystyle T} is the temperature (in kelvins), R {\displaystyle R} is the resistance at. T {\displaystyle T}
The British thermal unit (Btu) is a measure of heat, which is a form of energy. It was originally defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is also part of the United States customary units. [1] The SI unit for energy is the joule (J); one Btu equals about 1,055 J (varying ...
Since 1982, STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 10 5 Pa (100 kPa, 1 bar). NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa). [ 3 ] This standard is also called normal temperature and pressure (abbreviated as NTP).
These data correlate as ρ [g/cm3] = −8.461834×10−4T[°C] + 0.8063372 with an R2= 0.99999. Properties of aqueous ethanol solutions. [edit] Data obtained from Lange 1967. Mass fraction, Volume concentration, Mass concentration, g/(100 ml) at 15.56 °C. Density relative to 4 °C water [citation needed] Density at 20 °C relative to 20 °C water.
178.0 K (–95.1 °C), 1.23 Pa Critical point: 507.6 K (234.5 °C), 3020 kPa Std enthalpy change of fusion, Δ fus H o: 13 kJ/mol Std entropy change of fusion, Δ fus S o: 70 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o: 28.85 kJ/mol at 68.8 °C Std entropy change of vaporization, Δ vap S o? J/(mol·K) Solid properties Std ...
Data obtained from Lange's Handbook of Chemistry, 10th ed. and CRC Handbook of Chemistry and Physics 44th ed. The annotation, d a °C/ b °C, indicates density of solution at temperature a divided by density of pure water at temperature b known as specific gravity. When temperature b is 4 °C, density of water is 0.999972 g/mL. % wt. methanol.
Pre-exponential factor. In chemical kinetics, the pre-exponential factor or A factor is the pre-exponential constant in the Arrhenius equation (equation shown below), an empirical relationship between temperature and rate coefficient. It is usually designated by A when determined from experiment, while Z is usually left for collision frequency.