Physical states of matter

If a bottle of ammonia solution is opened in one corner of the laboratory, we can soon smell its familiar odor in all parts of the room. The ammonia gas escaping from the solution demonstrates that gaseous particles move freely and rapidly and tend to permeate the entire area into which they are released. 

Although matter is discontinuous, attractive forces exist that hold the particles together and give matter its appearance of continuity. These attractive forces are strongest in solids, giving them rigidity they are weaker in liquids but still strong 

A large crystal of table salt. A salt crystal is composed of a three-dimensional array of particles. 

TABLE 1.1 ] Common Materials in the Solid, Liquid, and Gaseous States of Matter 

TABLE 1.2 1 Physical Properties of Soiids, Liquids, and Gases  

In the past, especially in the United States, molar quantities were commonly denoted with an overhar (e.g., Vi). 

A phase is a region of the system in which each intensive property (such as temperature and pressure) has at each instant either the same value throughout (a uniform or homogeneous phase), or else a value that varies continuously from one point to another. Whenever this book mentions a phase, it is a uniform phase unless otherwise stated. Two different phases meet at an interface surface, where intensive properties have a discontinuity or change over a small distance. 

Some intensive properties (e.g., refractive index and polarizability) can have directional characteristics. A uniform phase may be either isotropic, exhibiting the same values of these properties in all directions, or anisotropic, as in the case of some solids and liquid crystals. A vacuum is a uniform phase of zero density. 

Suppose we have to deal with a nonuniform region in which intensive properties vary continuously in space along one or more directions—for example, a tall column of gas in a gravitational field whose density decreases with increasing altitude. There are two ways we may treat such a nonuniform, continuous region either as a single nonuniform phase, or else as an infinite number of uniform phases, each of infinitesimal size in one or more dimensions. 

We are used to labeling phases by physical state, or state of aggregation. It is common to say that a phase is a solid if it is relatively rigid, a liquid if it is easily deformed and relatively incompressible, and a gas if it is easily deformed and easily compressed. Since these descriptions of responses to external forces differ only in degree, they are inadequate to classify intermediate cases. 

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A dynamic equilibrium is a situation in which two (or more) opposing processes occur at the same rate so that no net change occurs. This is the kind of equilibrium that is established between two physical states of matter, e.g., between a liquid and its vapor, in which the rate of evaporation is equal to the rate of condensation in a closed container ... 

The previous chapter dealt with chemical bonding and the forces present between the atoms in molecules. Forces between atoms within a molecule are termed intramolecular forces and are responsible for chemical bonding. The interaction of valence electrons between atoms creates intramolecular forces, and this interaction dictates the chemical behavior of substances. Forces also exist between the molecules themselves, and these are collectively referred to as intermolecular forces. Intermolecular forces are mainly responsible for the physical characteristics of substances. One of the most obvious physical characteristics related to intermolecular force is the phase or physical state of matter. Solid, liquid, and gas are the three common states of matter. In addition to these three, two other states of matter exist—plasma and Bose-Einstein condensate. 

These ideas are evident in an essay of Lavoisier s from 1773, in which he identifies the three different physical states of matter solid, liquid, and gas. Here he makes the crucial distinction between the physical and chemical nature of substances, which confused the ancients and led to their minimal elemental schemes. The same bod/, says Lavoisier, can pass successively through each of these states, and in order to make this phenomenon occur it is necessary only to combine it with a greater or lesser quantity of the matter of fire. ... 

The stability of a metal crystallite on a support surface towards migration depends on its physical state of matter. At temperatures much lower than the melting point, near the Taroman temperature (0.4 times the melting temperature), metal crystallites are observed to develop liquid-like properties that apparently enhance their ability to migrate [121. This is particularly true in the presence of H2 [25]. Tamman temperatures for typical catalytic metals are 500 to 1100 K and for Pt and Ni, 817 and 690 K respectively [18]. Thus, crystallite migration may become an important mechanism for sintering of these two important metals above 700-800 K. 

A physical state of matter which exists at extremely high temperatures in which all molecules are dissociated and most atoms are ionized. 

W e have already pointed out that the military term smoke comprehends two b Lsically different phenomena (1) an aerial concentration of minute solid particles resulting from combustion, and (2) an aerial concentration of minute liquid particles resulting from chemical reactions not involving combustion. Neither of these phenomena can be scientifically clasafied into any of the three standard physical states of matter. On the contraiy, both are dispersed forms of matter, known as coUoidid stispensions or solutions. 

What are the common physical states of matter, and how do they differ from one another ... 

Is the equilibrium that is established between two physical states of matter an example of static or dynamic equilibrium Explain your answer. 

We have already seen that around 70% of the human body is water and this should be no surprise since, following development of the primeval cells in the oceans, evolution has continued within an aqueous environment and exploited the unique properties of water to the best advantage to living systems. Water is the only naturally occurring inorganic liquid and is the only compound which occurs in nature in all three physical states of matter solid, liquid, and gas. The omnipotence of the roles of water in the human body may be seen by reference to Table 1.1. Water is used to provide bulk to the body and use is also made of its unusual chemical properties. 

Questions 1 through 6 concern the three physical states of matter solid, liquid, and gas. Which one or two states are described by each characteristic ... 

On the atomic conception of combination, constituents will only be combined relatively to perception and the same thing will be combined to one percipient, if his sight is not sharp while to the eye of Lynceus nothing will be combined (DG 1.10, 328a13f.), so that substances only appear mixed to us because we cannot distinguish the individual juxtaposed particles. If the ingredients were thus preserved, combination would not be an objective physical state of matter, which Aristotle thought there was no reason to accept. In fact, the atomic view has no real conception of... 

Think for a moment. What is the only common molecule that exists in all three physical states of matter (sohd, hquid, and gas) under natural conditions on earth This molecule is absolutely essential for life in fact, life probably arose in this substance. It is the most abundant molecule in the cells of living organisms (70-95%) and covers 75% of the earth s surface. Without it, cells quickly die, and without it the earth would not be a fit environment in which to live. By no w you have guessed that we are talking about the water molecule. It is so abundant on earth that we take this deceptively simple molecule for granted. 

Figure 1.2 The physical states of matter. The magnified (blow-up) views show the atomic-scale arrangement of the particles in the three states of matter.

A gas is a physical state of matter generally characterized by low density and viscosity and the abilities to greatly expand and contract with changes in temperature and pressure, mix completely with other gases, and occupy any container uniformly. These features are particularly striking when contrasted to the other states of matter, liquid and solid. See Terminology, Liquid, p.241. Terminology, Solid, p.247. 

Let us first discuss the phase diagram of water. The phase diagrams show the thermodynamically stable physical states of matter at different temperatures and pressures. Within each phase, the material is uniform with respect to its chemical composition and physical state. At typical temperatures and pressures on Earth (T = 298 K (25°C) andV = 1 atm) water is a liquid, but it becomes solid (that is, ice) if its temperature is lowered below 273 K (0°C) and gaseous (that is, water vapor) if its temperature is raised above 373 K (100°C), at the same pressure. Each line (phase coexistence line) on a phase diagram represents a phase boundary and gives the conditions when two phases may stably coexist (in any relative proportions) [1]. 

Formaldehyde can polymerize in an anhydrous form in all three physical states of matter as a gas, as a liquid, or as a solid. It also polymerizes in water with acid catalysts. Many Lewis acids are efficient catalysts for this reaction. In addition, some protonic acids are also effective. Among them are perchloric and sulfuric acids and monoesters of sulfuric acid. ... 

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