Phase of matter

Nearly all matter is a solid, a liquid, or a gas. These forms are called phases of matter. 

Solids have a definite, or fixed, shape and volume. Their shape stays the same and they take up a certain amount of space. They are often very hard, or rigid. The molecules are usually locked in position. Molecules are made of at least two atoms. The colder a solid is, the less the molecules move. 

The molecules of a solid will start to move as they are heated. Most metals in the periodic table are solids at room temperature. Silver bricks are a solid. 

The desks, chairs, and books are solids in this classroom. They will hold their shape unless physically changed. 

Liquids have a fixed volume but not a fixed shape. The molecules in a liquid vibrate and move around each other easily. This means that they are fluid. Some liquids are thin, like water. It pours quickly. Other liquids are thick, like oil or syrup. They pour more slowly. 

Every day you encounter substances that exist in different phases—the air you breathe, the water you drink, and your mom s wooden cooking spoon. This chapter will take a closer look at the phases of matter and the changes in phase that matter can undergo. 

In addition to these basic properties, there are a number of theories and laws that tell more about how gases behave. These are the major focus of this chapter. 

The behavior of gases can further be explained with Kinetic Molecular Theory or KMT. KMT tells the following  

Gases exert a pressure on other objects as they collide. This pressure exerted by a gas can be defined as the amount of force exerted on an area. Anyone who has watched or listened to a weather report can recall hearing about the barometric pressure or atmospheric pressure. These pressures can differ as high and low pressure systems move across a particular region. There are two devices used to measure pressure exerted by gases, the mercury barometer and the manometer. Both devices can be useful depending upon the situation. 

There are a number of units that can be used to measure barometric pressure. For example, millimeters can be converted into inches thus, a standard pressure of 760 mm Hg can also be recorded as 30.0 inches of mercury. Inches of mercury are the units used for weather reports in the United States. Three other very common units that correspond to 760 mm Hg are  

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Colliiigs P J 1990 Liquid Crystals. Nature s Delicate Phase of Matter (Princeton Princeton University Press)... 

Liquid crystals represent a state of matter with physical properties normally associated with both soHds and Hquids. Liquid crystals are fluid in that the molecules are free to diffuse about, endowing the substance with the flow properties of a fluid. As the molecules diffuse, however, a small degree of long-range orientational and sometimes positional order is maintained, causing the substance to be anisotropic as is typical of soflds. Therefore, Hquid crystals are anisotropic fluids and thus a fourth phase of matter. There are many Hquid crystal phases, each exhibiting different forms of orientational and positional order, but in most cases these phases are thermodynamically stable for temperature ranges between the soHd and isotropic Hquid phases. Liquid crystallinity is also referred to as mesomorphism. 

LIQUIDS AND SOLIDS CONDENSED PHASES OF MATTER CHAP. 5... 

General reviews of the structure and properties of liquid crystals can be found in the following G. H. Brown, J. W. Doane, and V. D. Neff. "A Review of the Structure and Physical Properties of Liquid Crystals." CRC Press, Cleveland, Ohio, 1971 P. J. Collings and M. Hind, Introduction to Liquid Crystals. Nature s Delicate Phase of Matter," Taylor and Francis, Inc., Bristol. Pennsylvania, 1997 P. J. Collins, "Liquid Crystals. Nature s Delicate Phase of Matter," Princeton University Press. Princeton. New Jersey, 1990. A thermodynamic description of the phase properties of liquid crystals can be found in S. Kumar, editor, "Liquid Crystals in the Nineties and Beyond, World Scientific, Riven Edge, New Jersey, 1995. 

Intermolecular forces are responsible for the existence of several different phases of matter. A phase is a form of matter that is uniform throughout in both chemical composition and physical state. The phases of matter include the three common physical states, solid, liquid, and gas (or vapor), introduced in Section A. Many substances have more than one solid phase, with different arrangements of their atoms or molecules. For instance, carbon has several solid phases one is the hard, brilliantly transparent diamond we value and treasure and another is the soft, slippery, black graphite we use in common pencil lead. A condensed phase means simply a solid or liquid phase. The temperature at which a gas condenses to a liquid or a solid depends on the strength of the attractive forces between its molecules. 

The liquid phase of matter is the most difficult to visualize. We have seen that a gas-phase molecule moves with almost complete freedom. The intermolecular forces from other molecules are minimal, and movement is highly disordered. In the solid phase, a molecule is locked in place by intermolecular forces and can only oscillate around an average location. The liquid phase lies between the extremes of the gas and solid phases. The molecules are mobile, blit they cannot escape from one another completely. 

In their initial stndies, Pallant and Tinker (2004) found that after learning with the molecular dynamic models, 8th and 11th grade students were able to relate the difference in the state of matter to the motion and the arrangement of particles. They also used atomic or molecular interactions to describe or explain what they observed at the macroscopic level. Additionally, students interview responses included fewer misconceptions, and they were able to transfer their understanding of phases of matter to new contexts. Therefore, Pallant and Tinker (2004) concluded that MW and its guided exploration activities could help students develop robust mental models of the states of matter and reason about atomic and molecular interactions at the submicro level. 

Matter can also be categorized into three distinct phases solid, liquid, and gas. An object that is solid has a definite shape and volume that cannot be changed easily. Trees, automobiles, ice, and coffee mugs are all in the solid phase. Matter that is liquid has a definite volume but changes shape quite easily. A liquid flows to take on the shape of its container. Gasoline, water, and cooking oil are examples of common liquids. Solids and liquids are termed condensed phases because of their well-defined volumes. A gas has neither specific shape nor constant volume. A gas expands or contracts as its container expands or contracts. Helium balloons are filled with helium gas, and the Earth s atmosphere is made up of gas that flows continually from place to place. Molecular pictures that illustrate the three phases of matter appear in Figure 1-12. 

Atomic views of the three different phases of matter. 

Particles whose dimensions are between 1 nanometer and 1 micrometer, called colloids, are larger than the t3/pical molecule but smaller than can be seen under an optical microscope. When a colloid is mixed with a second substance, the colloid can become uniformly spread out, or dispersed, throughout the dispersing medium. Such a dispersion is a colloidal suspension that has properties intermediate between those of a true solution and those of a heterogeneous mixture. As Table 12-3 demonstrates, colloidal suspensions can involve nearly any combination of the three phases of matter. Gas-gas mixtures are the exception, because any gas mixes uniformly with any other gas to form a true solution. 

C14-0122. At its triple point, a dynamic equilibrium can exist among all three phases of matter. Draw a molecular picture of argon that shows what happens at the triple point. What is AG for each of the processes under these conditions Describe the matter and energy dispersal taking place for each of the processes. 

With foams, one is dealing with a gaseous state or phase of matter in a highly dispersed condition. There is a definite relationship between the practical application of foams and colloidal chemistry. Bancroft (4) states that adopting the very flexible definition that a phase is colloidal when it is sufficiently finely divided, colloid chemistry is the chemistry of bubbles, drops, grains, filaments, and films, because in each of these cases at least one dimension of the phase is very small. This is not a truly scientific classification because a bubble has a film round it, and a film may be considered as made up of coalescing drops or grains. ... 

The ability of XB to control recognition, self-organization, and self-assembly processes in the different phases of matter is clearly emerging in the literature. This chapter focusses on self-assembly in the solid phase, while the chapters of B. Duncan and A. Legon (in this volume) deal with the liquid crystalline phase and gas phase, respectively. Relatively few papers are reported in the literature on self-assembly processes in solution [66-68,207,208]. Several analytical techniques have been used to detect XB formation, to define its nature, to establish its energetic and geometric characteristics, and to reveal... 

Chemical reactions may result from interactions among and between the three phases of matter solid, liquid, and gas. The major interactions that occur in the deep-well environment are those between different liquids (injected waste with reservoir fluids) and those between liquids and solids (injected wastes and reservoir fluids with reservoir rock). Although gases may exist, they are usually dissolved in liquid at normal deep-well pressures. 

At what temperature and density does the phase transition to quark matter occur To determine the phase diagram of thermodynamic QCD is an outstanding problem. The phases of matter are being mapped out by colliding heavy-ions and by observing compact stars. Since QCD has only one intrinsic scale, Aqcd> the phase transition of QCD matter should occur at that scale as matter is heated up or squeezed down. Indeed, recent lattice QCD calculations... 

In our case, nearly equal volume fractions of the two quark phases are likely to form alternating layers (slabs) of matter. The energy cost per unit volume to produce such layers scales as a2/3(r 2SC — niN )2/3 where a is the surface tension [25], Therefore, the quark mixed phase is a favorable phase of matter only if the surface tension is not too large. Our simple estimates show that max < 20 MeV/fm2. However, even for slightly larger values, 20 < a < 50 MeV/fm2, the mixed phase is still possible, but its first appearance would occur at larger densities, 3po < Pn < 5po. The value of the maximum surface tension obtained here is comparable to the estimate in the case of the hadronic-CFL mixed phase obtained in Ref. [26], The thickness of the layers scales as a1 /3(r/i2 SY -) — niN ) 2/3 [25], and its typical value is of order 10 fm in the quark mixed phase. This is similar to the estimates in various hadron-quark and hadron-hadron mixed phases [25, 26], While the actual value of the surface tension in quark matter is not known, in this study we assume that it is... 

Under the assumptions that the effect of Coulomb forces and the surface tension is small, the mixed phase of normal and 2SC quark matter is the most favorable neutral phase of matter in the model at hand with r/ = 0.75. This should be clear from observing the pressure surfaces in Figs. 7 and 8. For a given value of the baryon chemical potential /i = fin/3, the mixed phase is more favorable than the gapless 2SC phase, while the gapless 2SC phase is more favorable than the neutral normal quark phase. 

Figure 1. Chemical potentials of the three phases of matter (H, Q, and Q ), as defined by Eq. (2) as a function of the total pressure (left panel) and energy density of the H- and Q-phase as a function of the baryon number density (right panel). The hadronic phase is described with the GM3 model whereas for the Q and Q phases is employed the MIT-like bag model with ms = 150 MeV, B = 152.45 MeV/fm3 and as = 0. The vertical lines arrows on the right panel indicate the beginning and the end of the mixed hadron-quark phase defined according to the Gibbs criterion for phase equilibrium. On the left panel P0 denotes the static transition point.

To summarize, in the present scenario pure hadronic stars having a central pressure larger than the static transition pressure for the formation of the Q -phase are metastable to the decay (conversion) to a more compact stellar configuration in which deconfined quark matter is present (i. e., HyS or SS). These metastable HS have a mean-life time which is related to the nucleation time to form the first critical-size drop of deconfined matter in their interior (the actual mean-life time of the HS will depend on the mass accretion or on the spin-down rate which modifies the nucleation time via an explicit time dependence of the stellar central pressure). We define as critical mass Mcr of the metastable HS, the value of the gravitational mass for which the nucleation time is equal to one year Mcr = Miis t = lyr). Pure hadronic stars with Mh > Mcr are very unlikely to be observed. Mcr plays the role of an effective maximum mass for the hadronic branch of compact stars. While the Oppenheimer-Volkov maximum mass Mhs,max (Oppenheimer Volkov 1939) is determined by the overall stiffness of the EOS for hadronic matter, the value of Mcr will depend in addition on the bulk properties of the EOS for quark matter and on the properties at the interface between the confined and deconfined phases of matter (e.g., the surface tension a). 

Since the discovery of the parton substructure of nucleons and its interpretation within the constituent quark model, much effort has been spent to explain the properties of these particles and the structure of high density phases of matter is under current experimental investigation in heavy-ion collisions [17]. While the diagnostics of a phase transition in experiments with heavy-ion beams faces the problems of strong non-equilibrium and finite size, the dense matter in a compact star forms a macroscopic system in thermal and chemical equilibrium for which effects signalling a phase transition shall be most pronounced [8],... 

Recently the term, gas-expanded liquids (GXLs) [6-8] has been used to describe these unique mixtures while others use the term subcritical mixtures to describe the phase of matter. No matter what term is used to describe these mixtures one point should be clear all of these mixtures are liquids not supercritical fluids. Eurthermore, there is no discontinuity observed in moving from the supercritical condition to a liquid. However, EEL mixtures and supercritical fluids are two different phases of matter. 

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