Numerical value of coefficient of diffusion at liquids is much less than at gases. For example the coefficient of diffusion of NaCl is equal in water 1,1·10-9 sq.m / with while for diffusion of argon in helium it is equal 7·10-5 sq.m/pages.
With temperature increase density and pressure of saturated steam increase. The temperature is higher, the bigger number of molecules of liquid possesses the energy sufficient for evaporation, and the bigger, there has to be steam density that condensation could be made even to evaporation.
The amount of heat which needs to be brought isothermal to evaporate a certain amount of liquid, with the external pressure equal to pressure of its saturated steam, is called as the hidden warmth of steam formation. Usually this size is correlated to one gram, or to one I ask. The amount of heat necessary for isothermal evaporation asking liquids is called as the molar hidden warmth of steam formation. If to divide this size into molecular weight, the specific hidden heat of steam formation will turn out.
Temperature of boiling is that temperature at which pressure of saturated steam becomes equal to external pressure. At increase in pressure temperature of boiling increases, and at reduction - decreases.
Because of change of pressure in liquid with height of its column, boiling at various levels in liquid happens, strictly speaking, at various temperature. Only saturated steam over a surface of the boiling liquid has a certain temperature. Its temperature is defined only by external pressure. This temperature means when speak about boiling temperature.
It is obvious that liquid will be that less viscous, than t time between jumps of molecules that is, than more often there are jumps is less. Proceeding from it, it is possible to write expression for the coefficient of viscosity called by Frenkel's equation – Andrade:
Heat conductivity in liquids takes place in the presence of temperature gradient. Thus energy in liquids is transferred in process of collision of the fluctuating particles. Particles with higher energy make fluctuations with a bigger amplitude, and at collisions with other particles as if shake them, transferring them energy. Such mechanism of transmission of energy does not provide its fast transfer. Therefore heat conductivity of liquids is very small.
The internal friction of liquids arises at the movement of liquid because of transfer of an impulse in the direction, perpendicular to the direction of the movement. Transfer of an impulse from one layer in another is carried out at jumps of molecules about which it was told above.