* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Physical concept of the surface tension of the liquid until some time
Rotational spectroscopy wikipedia , lookup
Liquid crystal wikipedia , lookup
Host–guest chemistry wikipedia , lookup
Eigenstate thermalization hypothesis wikipedia , lookup
Rotational–vibrational spectroscopy wikipedia , lookup
Transition state theory wikipedia , lookup
Heat transfer physics wikipedia , lookup
X-ray photoelectron spectroscopy wikipedia , lookup
Thermal radiation wikipedia , lookup
Vapor–liquid equilibrium wikipedia , lookup
Coupled cluster wikipedia , lookup
Nanofluidic circuitry wikipedia , lookup
Rutherford backscattering spectrometry wikipedia , lookup
State of matter wikipedia , lookup
Work (thermodynamics) wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Surface properties of transition metal oxides wikipedia , lookup
Ultrahydrophobicity wikipedia , lookup
Equation of state wikipedia , lookup
The physical nature of liquid surface tension Khaidarov G. G., Khaidarov A. G. St. Petersburg State Technological Institute (technical university), 26 Moskovsky Prospect, Saint-Petersburg, 190013, Russia Email: [email protected] Abstract: It is proved that the physical concept of liquid surface tension is a part of the concept of internal energy. The physical model of liquid evaporation and formula obtained for calculating surface tension of the liquid are suggested. The formula was tested on reference values for 64 substances in the temperature range from −253 to +200 degrees Celsius. A unified concept for physical notions of surface tension and the internal energy of the liquid is also obtained. A physical model is agreed with the views of the other authors. The result of this model is formulas for calculating values of specific heats for one- and two atomic gas. It was proved that surface tension is a part of internal energy. As a result a theoretical model is suggested and a theoretical calculation between surface tension and temperature is established. This dependence is confirmed by calculation of empirical data from the reference manual of thermophysical properties. Keywords: surface tension, internal energy, specificheat, gas, molecule, heat of vaporization, liquid, surface tension, internal energy, temperature, theory, theoretical, dependent, relationship, empirical, data. Physical concept of the liquid tension remained unclear for some time. In the early 20th century Frenkel Y. presumed the existence of a distinct linkage between tension coefficient and other physical quantities, nevertheless he did not formularize it. Langmuir I. pointed out to a ceratin derivative of the enthalpy without specifying it. Currently the geometric models of substance evaporation explained the physical nature of liquid tension. Thus, the essence of surface tension was proved to be a part of the internal energy of matter. Further you can find a brief statement of this concept and its development. There exist two geometric models. One of them – a theoretical “unpacking” model, published by Khaidarov G.G. in 1983 [1], along with the theoretical development of the calculating formula. The second one is a theoretical model of «salami method», published by academician Victor F. Weisskopf (1985) [2,3]. Later on similar theoretical models were published by a number of authors with the development of similar formulas. See example [4]. Theoretical models of «unpacking» - method of 1983 and «salami method» of 1985 are based on the same principle of geometrical modeling of physical phenomenon. At first rough approximation we can formulate a model of «unpacking» in the following way. The evaporation of the molecules of the substance is regarded as a breaking of molecular bonds in respect of neighbouring molecules of the substance in all six directions of the axes (x, -x, y, - y, z, -z) with further agitating of molecules in a gas volume. The application of the surface tension coefficient of a substance' s molecules implies breaking bonds in one of the six directions, vertical to the cleavage surface. Another interpretation is: an internal energy characterizes the six cleavages along the axes of reference (x, -x, y, -y, z, -z), and the surface tension is characterized by one cleavage - so called «unpacking» method. The difference between the two concepts mentioned above is solely in the geometric interpretations of the evaporation process and surface tension, as well as in the areas of application of these theoretical studies. In the theory of the «unpacking» - method of 1983 [1] in contrast to the «salami method», the general concept apart there has been published the end formula for calculation of surface tension for substances. The formula was tested with reference data for 64 substances in a temperature range from –253 to +200 degrees by Celsius. Subject to the regularities of Clapeyron - Mendeleev formula for determining the coefficient of liquid tension can be written in terms of the specific heat of vaporization as: (1) or in terms of internal energy U, as : (2) where r is the heat of vaporization, J/kg; ; – is the liquid density, kg/ m3; is the vapour density, kg/ m3; R is the universal gas constant, J/(mol * K); T - temperature, K; U is the internal energy of liquid, J/kg; M - molecular mass, kg/Kmol; N - Avogadro constant, Kmol-1. The validity of the formula (1) was determined according to the estimated value of coefficient of molecules efficiency, which equals to the ratio of the effective radius of a real molecule to the theoretical radius of the symmetric spherical molecule. , where n is the index of the molecule efficiency. As a result of calculations for molecules, similar in the symmetric spherical form , the coefficient n must be equal to unity. The processing of the reference data of the thermophysical properties of most substances has confirmed the theoretical formulas with an accuracy of 15%. Some substances with asymmetric form possess a factor of the molecule efficiency different from the unit. Further development of the «unpacking» model in 2010-2012s has proved the applicability of the «unpacking» concept for the theoretical explanation of interdependency of physics and physical chemistry. A conclusion of this «unpacking» model is that of a reliable agreement with the molecular - kinetic theory of ideal gases. Namely, the theoretical development of the relationship of heat capacity values for one-, two - and triatomic gases. An impact of the spatial arrangement of atoms on the heat capacity of the molecule has been proved[5]. Another conclusion of the «unpacking» model is a theoretical development of the formula for determining the influence of the temperature on the surface tension. The formula is in good agreement with the well-known empirical dependence of Eötvös rule. Theoretically the values of empirical coefficients of proportionality have been derived[6]. The formula was tested according to the data from the Reference book on thermophysical properties of gases and liquids. Additionally, the calculations were performed by the formulas (1), (2) according to the data from the directory for metals. The results confirmed the applicability of the concept of «unpacking» to the upper limit temperature of 1100 degrees Kelvin [6]. More detailed information about the theory of «unpacking» and its consequences can be found in a free access in Internet, Wikipedia ( ru.wikipedia.org ) and ( ru.wikibooks.org) in Russian, typing in search box «Surface tension». References 1. Khaidarov G. G.// Russian Journal of Physical Chemistry A (Zhurnal fizicheskoi khimii). 1983, No. 10, p. 2528–2530. 2. Weisskopf V. F. Search for simplicity // Am. J. Phys. 1985. Vol. 53. No. 1. P. 19–20. 3. Weisskopf V. F. Search for simplicity: the size of molecules revisited // Am. J. Phys. 1985. Vol. 53. No. 7. P. 618–619. 4. Garai J. Physical model for vaporization // Fluid Phase Equilibria. 2009. Vol. 183. P. 89– 92. 5. Khaidarov G. G., Khaidarov A. G., Mashek A.Ch. The physical nature of liquid surface tension // Vestnik St.Petersburg University. Ser. 4. 2011. Issue. 1. P. 3–8. 6. Khaidarov G. G., Khaidarov A. G., Mashek A.Ch., Maiorov E. E. Temperature Influence on Surface Tension // Vestnik St.Petersburg University. Ser. 4. 2012. Issue. 1. P. 21–25.