What Is a Liquid

It is well known from studies of the properties of matter that the liquid state is much more complex than either the gaseous or solid states. Studies of the properties of gases quickly lead to the ideal gas law, which describes the properties of real gases at low pressures and high temperatures. This success is clearly due to 

On the other hand, solids are characterized by a very ordered structure in which each ion or molecule is surrounded by a fixed number of neighbors whose nature and orientation are determined by the interparticle forces in the crystal. These may be chiefly ion-ion interactions, as in an ionic crystal, or intermolecular forces, as in a molecular crystal. Because of the high state of order in crystals it is a reasonably straightforward problem to calculate their thermodynamic properties on the basis of quite simple statistical mechanical models. 

One way of conceptualizing a liquid is as a very disordered solid. If one disrupts the structure of the nearest neighbors around a reference molecule in a molecular crystal, the effect of the disruption extends quite far. As a result, there is some local order around the reference point but the extent of order falls off rapidly with distance so that at distances equivalent to four or five molecular diameters the system does not possess order with respect to the reference point. Theories of the liquid state based on an approach involving disordered solids were pursued from the 1930s to the 1960s but did not meet with much success. On the other hand, the liquid may be regarded as an extremely imperfect gas. In this approach, which has been quite successful, the statistical mechanical techniques used to describe the properties of non-ideal gases are extended to liquids. 

Liquids may be classified according to the intermolecular (or interatomic) forces existing between the components. In this way, seven different kinds of liquids may be identified  

The simplest liquids are those formed by the inert gases. He, Ne, Ar, etc. These atoms interact via van der Waals forces and strongly repel each other at short interatomic distances. 

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Barker J A and Henderson D 1976 What is a liquid Understanding the states of matter Rev. Mod. Phys. 48 587... 

What is a liquid aerosol A foam Give two examples of each. 

What Is a Liquid 13.5 Boiling Point 13.8 The Hydrogen Bond... 

When introducing the subject of liquid crystals, the first and most important question to be answered is, What is a liquid crystal Unlike the more well-known varieties of soft matter, such as polymers or gels, liquid crystals are often something of a mystery to the nonspecialist, although a simple definition can be made for the wide variety of materials that can exhibit liquid crystalline properties. 

A useful device to have installed in a stirred autoclave is a liquid sampling tube by which liquid samples are withdrawn under pressure through a filter attached to the lower end of the tube. This device is especially useful for analysis of reaction progress and supplements information obtained from pressure-drop determinations. It is much easier to improve a less than satisfactory yield, if it can be determined what is going wrong and when. For academically orientated persons, a study of the rise and decline of various reaction products, as a function of reaction parameters and catalyst, can be a fertile source of useful publications. 

Few non.chemists know exactly what an epoxide is. but practically everyone has used an "epoxy glue for household repairs or an epoxy resin for a protective coating. Epoxy resins and adhesives generally consist of two components that are mixed just prior to use. One component is a liquid "prepolymer/ and the second is a "curing agent" that reacts with the prepolymer and causes it to solidify. 

The batch system of heating is to be replaced by a continuous countercurrent heat exchanger in which the heating medium is a liquid entering at 388 K and leaving at 333 K. If the heat transfer coefficient is 250 W/m2 K, what heat exchange area is required Neglect heat losses. 

Pentane is a liquid with a vapor pressure of 512 Torr at 25°C at the same temperature, the vapor pressure of hexane is only 151 Torr. What composition must the liquid phase have if the gas-phase composition is to have equal partial pressures of pentane and hexane ... 

C12-0046. Mercury is the only metallic element that is a liquid at room temperature. What kinds of solids would you expect to be soluble in liquid mercury ... 

What is a major advantage of using fast atoms rather than ions as bombarding particles in desorption ionization using a liquid matrix (i.e., FAB) (eliminates charging, which can lead to signal instability). 

A quite serious problem, however, still obscures most applications of the percolation theory to the transport of magmas. Most major elements, such as Si, Mg, Ca,... can be considered as compatible since their concentration in the peridotite source and the basaltic melt are similar within a factor of 3. Equation (9.4.37) indicates, as would equations (8.3.17) and (8.3.19) in the most general case, that major elements are slower than the liquid, especially for small porosities. But, what is the liquid made of, then The velocity of a medium is the weighted average velocity of its constituents [see equation (8.1.4)]. The basalt velocity is that of Si, Mg, Ca,... weighted by their... 

What is a supercritical fluid Why are supercritical fluids useful in solid-liquid extraction ... 

To obtain a relation between Ln and Lm, it is necessary to make an enthalpy balance over the feed plate, and to consider what happens when the feed enters the column. If the feed is all in the form of liquid at its boiling point, the reflux Lm overflowing to the plate below will be Ln + F. If however the feed is a liquid at a temperature Tf, that is less than the boiling point, some vapour rising from the plate below will condense to provide sufficient heat to bring the feed liquor to the boiling point. 

At this point in our discussion about chemical bonds and structural formulas, we should stress that structural isomers may exhibit very different properties and reactivities. For example, the rates of hydrolysis (reaction with water, see Chapter 13) of the four butyl chlorides shown in Fig. 2.1 are quite different. While the hydrolytic half-life (time required for the concentration to drop by a factor of 2) of the first and third compound is about 1 year at 25°C, it is approximately 1 month for the second compound, and only 30 seconds for the fourth compound. When we compare the two possible structural isomers with the molecular formula C2H60, we can again find distinct differences in that the well-known ethanol (CH3CH2OH) is a liquid at ambient conditions while dimethylether (CH3OCH3) is a gas. These examples should remind us that differences in the arrangement of a single collection of atoms may mean very different environmental behavior thus we must learn what it is about compound structure that dictates such differences. 

What is a large and what is a small structure In practice this is a relevant question because for small structures we can neglect pgh and use the simpler equation. Several authors define the capillary constant y/2 /pg (as a source of confusion other authors have defined y/jJpg as the capillary constant). For liquid structures whose curvature is much smaller than the capillary constant the influence of gravitation can be neglected. At 25° C the capillary constant is 3.8 mm for water and 2.4 mm for hexane. 

Atoms in a liquid are packed together in a defined space in a semi-organized way, but those atoms are able to move around freely and sometimes mix in unpredictable ways. Unlike solids, there is no set organization or strong bonding between atoms in a liquid. But like a solid, the forces between atoms are what make a liquid a liquid, giving this state of matter its own unique properties. Liquids can mix, spill, and change shape easily. 

You see we have here drawn something, which we have not known about before, out of this solution. Let us now take that flask from Mr. Andersen s hands, and see what we can draw out of that. This, you know, is a liquid which we have just made up from copper and nitric acid, whilst our other experiments were in hand and though I am making this experiment very hastily, and may bungle a little, yet I prefer to let you see what I do rather than prepare it beforehand. 

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