Condensed phase Liquid Solid

The refractive index has as its basis the fact that light travels at a different velocity in condensed phases (liquids, solids) than in air. The refractive index n is defined as the ratio of the velocity of light in air to the velocity of light in the medium being... 

NOTE Above the horizontal line the condensed phase is solid below the line, it is liquid. = % K. 

Values recalculated into SI units from those of Din. Theimodynamic Functions of Gases, vol. 2, Butterworth, London, 1956. Above the solid line the condensed phase is solid below the line it is liquid, t = triple point c = critical point. 

Values extracted and in some cases rounded off from ttose cited in RaLinovict (ed.), Theimophysical Propeities of Neon, Ai gon, Kiypton and Xenon, Standards Press, Moscow, 1976. Ttis source contains values for tte compressed state for pressures up to 1000 bar, etc. t = triple point. Above tbe sobd line tbe condensed phase is solid below it, it is liquid. Tbe notation 5.646. signifies 5.646 X 10 . At 83.8 K, tbe viscosity of tbe saturated liquid is 2.93 X 10 Pa-s = 0.000293 Ns/ui . Tbis book was published in English translation by Hemisphere, New York, 1988 (604 pp.). 

This progress gives us substantial basis for confidence in the usefulness of the atomic theoiy and it encourages us to develop the model further. We shall see that the concepts we have developed in our consideration of gases are also useful when we consider the behavior of condensed phases—liquids and solids. 

A substance vaporizes from a condensed phase (liquid or solid) into the gas phase, so A ra (gas) = 1 mol. The change in volume for this type of transformation is almost equal to the volume of the resulting gas. For example, according to the ideal gas equation, one mole of water vapor at 373 K has a volume of 30.6 L ... 

For condensed phases (liquids and solids) the molar volume is much smaller than for gases and also varies much less with pressure. Consequently the effect of pressure on the chemical potential of a condensed phase is much smaller than for a gas and often negligible. This implies that while for gases more attention is given to the volumetric properties than to the variation of the standard chemical potential with temperature, the opposite is the case for condensed phases. 

The electrostatic inner potential, of a condensed phase (liquid or solid) is defined as the differential work done for a unit positive chaig e to transfer from fhe zero level at infinity into the condensed phase. In cases in which the condensed... 

Due to the fact that industrial composites are made up of combinations of metals, polymers, and ceramics, the kinetic processes involved in the formation, transformation, and degradation of composites are often the same as those of the individual components. Most of the processes we have described to this point have involved condensed phases—liquids or solids—but there are two gas-phase processes, widely utilized for composite formation, that require some individualized attention. Chemical vapor deposition (CVD) and chemical vapor infiltration (CVI) involve the reaction of gas phase species with a solid substrate to form a heterogeneous, solid-phase composite. Because this discussion must necessarily involve some of the concepts of transport phenomena, namely diffusion, you may wish to refresh your memory from your transport course, or refer to the specific topics in Chapter 4 as they come up in the course of this description. 

There are many ways in which electromagnetic waves can interact with matter in its condensed phases, liquid and solid. Some of these have been treated with simple models in Chapter 9, and examples are given in this chapter. Lest we leave the reader with an oversimplified view of optical constants we list in Table 10.2 several absorption mechanisms in solids together with the spectral regions in which they are important. References, primarily review articles and monographs, are also included to guide the reader in further study. 

A vast number of engineering materials are used in solid form, but during processing may be found in vapor or liquid phases. The vapor— solid (condensation) and liquid—>solid (solidification) transformations take place at a distinct interface whose motion determines the rate of formation of the solid. In this chapter we consider some of the factors that influence the kinetics of vapor/solid and liquid/solid interface motion. Because vapor and liquid phases lack long-range structural order, the primary structural features that may influence the motion of these interfaces are those at the solid surface. 

The Clapeyron equation can be simplified to some extent for the case in which a condensed phase (liquid or solid) is in equilibrium with a gas phase. At temperatures removed from the critical temperature, the molar volume of the gas phase is very much larger than the molar volume of the condensed phase. In such cases the molar volume of the condensed phase may be neglected. An equation of state is then used to express the molar volume of the gas as a function of the temperature and pressure. When the virial equation of state (accurate to the second virial coefficient) is used,... 

Consideration of the condition of equilibrium applied to reactions between pure condensed phases, liquid or solid only, leads to some interesting... 

A solution is defined as a condensed phase (liquid or solid) containing several substances. The main substance of the solution is called solvent and the other constituent substances dissolved in the solvent are solutes. Solutions are classified into ideal solutions and non-ideal solutions. For an ideal solution the chemical potential of a constituent substance i is given by ... 

The electrostatic inner potential 0 in a condensed phase (liquid or solid) consists of the outer potential rp and the surface potential % as shown in Fig. 9.1 and Eq. 9.2 ... 

Aerosols condensed phases of solid or liquid particles, suspended in state, that have stability to gravitational separation over periods of observation. 

The mass action law assumes that the reaction medium is homogeneous. In heterogeneous reactions (involving different substances in multiple phases), the densities and effective concentrations of pure condensed phases (liquids or solids) are constant. The concentrations of such species are set to unity in the equilibrium constant expression for such reactions. For example, given the following decomposition,... 

The solid white form really is only in a state of false equilibrium, being unstable with respect to the polymerised forms at all realisable temperatures. There are also the other forms—red, scarlet and black phosphorus—the behaviour of which under definite conditions of pressure and temperature cannot be stated with any certainty. Further, the melting-point even of the well-crystallised white phosphorus can be made fcto vary under certain conditions (see p. 15). In fact, all the condensed phases, liquid and solid, behave as mixtures rather than as single pure substances. 

Gallane condenses at low temperatures as a white solid that melts at ca. 223 K to form a colorless, viscous liquid. The rate of vaporization of the solid at 210 K is consistent with a vapor pressure on the order of 1 mm Hg. Samples of the material in the condensed phase (liquid or solution) decompose to the elements at temperatures in excess of 243 K. At a pressure of 10 mm Hg the vapor has a half-life of about 2 min at ambient temperatures. 

For any pure component in a condensed phase, whether solid or liquid, kept at steady conditions for sufficient time, can be considered to be in equilibrium with its vapour. For metallurgical systems, where vapour pressures are extremely small, close to equilibrium conditions are easily achieved in a very short time. The free energy change of conversion of condensed phase to vapour can be denoted as follows ... 

We would not discuss here the diffusion mechanisms and diffusion controlled processes. The treatment in complex and other comprehensive documents may be referred for this purpose. We would only emphasise the need to find means to circumvent diffusion steps in reactions involving condensed phases (either solids or liquids) as diffusion barriers often make industrial exploitation of process unviable. 

The equilibrium conditions for a reaction in a single, homogeneous, condensed phase (liquid or solid) can be related to the equilibrium conditions... 

Primary effects comprise recoil of the nucleus and excitation of the electron shell of the atom. The excitation may be due to recoil of the nucleus, change of atomic number Z or emission of electrons from the electron shell. Secondary effects and subsequent reactions depend on the chemical bonds and the state of matter. Chemical bonds may be broken by recoil or excitation. In gases and liquids mainly the bonds in the molecules are affected. The range of recoil atoms is relatively large in gases and relatively small in condensed phases (liquids and solids). Fragments of molecules are mobile in gases and liquids, whereas they may be immobilized in solids on interstitial sites or lattice defects and become mobile if the temperature is increased. 

The volatility of a species is the degree to which the species tends to transfer from the liquid (or solid) state to the vapor state. At a given temperature and pressure, a highly volatile substance is much more likely to be found as a vapor than is a substance with low volatility, which is more likely to be found in a condensed phase (liquid or solid). 

At 10 atm, FeO concentrations in silicates are minimal above 650 K and all condensed phases are solid. If the total pressure increases, condensation temperatures rise, but the sequence in which minerals condense does not change significantly except that silicate melts become stable at pressures above —10 atm. If condensation occurs in systems that have been enriched in dust relative to gas, FeO concentrations in silicates become appreciable at high temperatures (up to —1,100 K for 10 -fold dust enrichments), and liquids are also stabilized (Wood and Hashimoto, 1993 Ebel and Grossman, 2000). Pressures and temperatures at the midplane of the nebula vary considerably as the solar nebula... 

While eq N) is the largest principal component of the electric field gradient (EFG) tensor at the site of the quadrupolar nucleus. All the information about the structure of the molecule and interactions is in the eq N) term. In the gas-phase (at low symmetry positions) the EFG is entirely of intermolecular origin. In the condensed phases (liquids and solids), intermolecular interactions may have a substantial influence on the observed EFG. 

Atoms and molecules at surfaces and interfaces possess energies significantly different from those of the same species in the bulk phase. The term surface is usually reserved for the region between a condensed phase (liquid or solid) and a gas phase or vacuum, while the term interface is normally applied to the region between two condensed phases. 

A solution is, by definition, a condensed phase (liquid or solid) composed of several components. We must stress at the outset that, even in very dilute solutions, it is incorrect to compare the state of the dissolved components with that of molecules in the gas state. Each dissolved molecule is subject to strong forces exerted on it by solvent molecules. This point is clearly illustrated by the fact that the heat of solution of a solid is usually very close to the heat of fusion, and differs considerably from the heat of vaporization. For example, for naphthalene the heat of solution in a series of solvents varies from 4,180 to 5,110 cal./mole. The heat of fusion is 4,570 cal./mole while the heat of vaporization is 9,700 cal./mole. 

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