Some Properties of Liquids

Molecules at the surface are attracted only by other surface molecules and by molecules below the surface. Molecules in the interior experience forces from neighboring molecules in all directions. 

Surface tension is the energy, or work, required to increase the surface area of a liquid. Surface tension is often represented by the Greek letter gamma (7) and has the units of energy per unit area, typically joules per square meter (J m ). As the temperature—and hence the intensity of molecular motion— increases, intermolecular forces become less effective. Less work is required to extend the surface of a liquid, meaning that surface tension decreases with increased temperature. 

Water spreads into a thin film on a clean glass surface (left). If the glass is coated with oil or grease, the adhesive forces between the water and oil are not strong enough to spread the water, and droplets stand on the surface (right). 

They are used in applications ranging from dish washing to industrial processes. 

The viscosity of automotive motor oil is designated by its SAE number, such as 40 W. When compared in a ball viscometer (Fig. 12-15), the ball drops much faster through 10 W oil than through 40 W oil. Which of these two oils provides better winter service in the Arctic region of Canada Which is best suited for summer use in the American Southwest Which oil has the stronger intermolecular forces of attraction  

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Table 13.8 Some properties of liquid AsCh and SbCh...

Water is a volatile, mobile liquid with many curious properties, most of which can be ascribed to extensive H bonding (p. 52). In the gas phase the H2O molecule has a bond angle of 104.5° (close to tetrahedral) and an interatomic distance of 95.7 pm. The dipole moment is 1.84 D. Some properties of liquid water are summarized in Table 14.8 together with those of heavy water... 

Most scientists think of glass as an amorphous solid. Just to confuse matters, though, glass does have some properties of liquids, mainly its random arrangement of atoms, so there are some scientists who think of glass as its own state of matter, neither liquid nor solid. 

Surface and Interfacial Tension. Some properties of liquid surfaces are suggestive of a skin that exercises a contracting force or tension parallel to the surface. Mathematical models based on this effect have been used in explanation of surface phenomena, such as capillary rise. The terms surface tension (gas—liquid or gas—solid interface) and interfacial tension (liquid—liquid or liquid—solid) relate to these models which do not reflect the actual behavior of molecules and ions at interfaces. Surface tension is the force per unit length required to create a new unit area of gas—liquid surface (mN/m (= dyn/cm)). It is numerically equal to the free-surface energy. Similady, interfacial tension is the force per unit length required to create a new unit area of liquid—liquid interface and is numerically equal to the interfacial free energy. 

Some properties of liquid alloys. J. Iron Steel Inst. London 200, 95 (1962). 

Several gas laws have been introduced in this chapter, but no explanation as to why those laws apply to all gases has been proposed. This section introduces the kinetic molecular theory of gases, which explains the gas laws and when extended, also explains some properties of liquids and solids. Five postulates explain why gases behave as they do ... 

Bawden, F. C., and Pirie, N. W. The isolation and some properties of liquid crystalline substances from solanaceous plants infected with three strains of tobacco mosaic virus. Proc. Roy. Soc. (London) B123, 274-320 (1937). 

In the preceding sections, some properties of liquids were related to the nature and strength of intermolecular forces within them. 

THE DELTA PARAMETER AND ITS RELATION TO SOME PROPERTIES OF LIQUIDS. 

Figure 1.10. Some properties of liquid crystalline and crystal layered phases.

List some properties of liquids and solids that reflect the difference in e degree of order in the two states. 

The weak van der Waals potential between He atoms and the bosonic nature of He also are basic for understanding why He is the only bulk superfluid below Tc = 2.18 if at 0.05 bar. The rare isotope He, a fermion, on the other hand, only becomes superfluid at a three orders of magnitude lower temperature. There are many well known macroscopic manifestations of superfluidity such as (i) flow without resistance (ii) a vanishing viscosity (iii) the ability to creep out of vessels against the forces of gravity (iv) the fountain effect which is driven by a type of Maxwell demon which separates the superfluid from the normal fluid components and (v) an enormous thermal conductivity which is 30 times greater than that of copper. Table 7.1 compares some properties of liquid argon (also a cry-omatrix) with those of helium in the normal and in the superfluid state. 

Some Properties of Liquid-Crystal Polymer Networks... 

Some properties of liquid water computed with the TIP3P and TIP4P models are compared with experimental data in... 

Intermolecular Forces 12-2 Some Properties of Liquids 12-3 Some Properties of Solids 12-4 Phase Diagrams... 

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