![]() SRD 103a – Thermo Data Engine (TDE) for pure compounds. (TRC) data available from this site, much more physicalĪnd chemical property data is available from the In addition to the Thermodynamics Research Center Requires a JavaScript / HTML 5 canvas capable browser.Ĭoefficents calculated by NIST from author's data.Įnthalpy of phase transition ΔH trs (kJ/mol)Įntropy of phase transition ΔS trs (J/mol*K) ACĮnthalpy of vaporization (at saturation pressure) See also Ambrose, Counsell, et al., 1970. LouisĪverage of 138 out of 148 values Individual data pointsĪverage of 11 values Individual data pointsĪverage of 8 values Individual data pointsĪverage of 37 out of 38 values Individual data pointsĪverage of 18 out of 19 values Individual data pointsĪverage of 7 values Individual data pointsĪverage of 12 out of 13 values Individual data pointsīased on data from 293. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri - St. TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny directorīS - Robert L. Secretary of Commerce on behalf of the U.S.A. Your institution may already be a subscriber.įollow the links above to find out more about the dataīy the U.S. With the development of data collections included in The purpose of the fee is to recover costs associated NIST subscription sites provide data under theĭata Program, but require an annual fee to access. NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data).NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data).X-ray Photoelectron Spectroscopy Database, version 4.1.Computational Chemistry Comparison and Benchmark Database.Use this link for bookmarking this species This structure is also available as a 2d Mol file ![]() IUPAC Standard InChIKey: LFQSCWFLJHTTHZ-UHFFFAOYSA-N Copy.The recognised test methods are ASTM D4052 and ISO 12185, though many companies develop their own internal test methods based on these. This data can be read off a screen, printed out, or transferred to an appropriate electronic data storage system, e.g. An algorithm in the instrument translates the difference in the two frequencies to the density of the sample and the strength (concentration) of the ethanol. The two tubes are subjected to vibrational energy and the frequency of oscillation induced in each is measured electronically. A standard, normally copper inside a similar tube, is positioned alongside the sample tube in a temperature controlled cavity. In more detail, the procedure involves the introduction of the sample into a 1 mm glass U tube, avoiding the inclusion of air bubbles. ![]() The induced frequency will be a function of the density of the sample material. The principle applied in the most popular instruments relies on the measurement of the frequency of vibration induced in a sample placed in an oscillating glass U tube, compared to that of a material of known density. This method has largely been superseded in favour of much more sophisticated and accurate density meters, also called densitometers. The traditional method of density measurement was with appropriate hydrometers and the strength could be determined from density / strength tables, for a given temperature. Density variation with temperature is significant and must be catered for. Density of an ethanol water solution is an ideal measurement of ethanol content as there is a steady gradation in density from 0.7894 g/ml (pure ethanol at 20 0C) to 0.9982 g/ml for pure water at 20 0C. Since ethanol is miscible with water in all proportions, it is necessary to determine its strength (or concentration) for commercial purposes such as pricing (on pure ethanol content) and excise duty assessment. ![]()
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