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State physical

By physical state (or j ust state ) is meant a specific condition of a sample of matter that is described in terms of its physical form (g is, liquid, or solid) and the volume, pressure, temperature, and amount of substcuice present. (The precise meanings of these terms are described below.) So, 1 kg of hydrogen gas in a container of volume 10 dm at a specified pressure and temperature is in a particular state. The same mass of gas in a container of volume 5 dm is in a different state. Two samples of a given substance are in the same state if they are the same state of matter (that is, are both present as gas, liquid, or solid) and if they have the same mass, volume, pressure, and temperature. [Pg.5]

To report the physical state of a sample we need to specify a number of properties in terms of their appropriate units. The manipulation of units, which almost always will be from the International System of units (SI, from the French Syst me International d Unites) described in the Resource section, is explained in Mathematical toolkit F.l. These properties and their units include the following  [Pg.5]

2 kg of lead contains twice as much matter as 1 kg of lead and indeed twice as much matter as 1 kg of anything. For typical laboratory-sized samples it is usually more convenient to use a smaller unit and to express mass in grams (g), where 1 kg= lO g. [Pg.5]

For volume we write V= 100 cm if the sample occupies 100 cm of space. Units used to express volume include cubic meters (m ), cubic decimeters (dm ), liters (L), and milliliters (mL). The Hter is not an SI unit, but is exactly equal to 1 dm . [Pg.5]

Physical quantities are denoted by italic, and sometimes Greek, letters (as in m for mass or p for mass density). Units are denoted by Roman letters (as in m for meter). [Pg.5]

Chemicals exist as gases, liquids or solids. Solids have definite shapes and volume and are held together by strong intermolecular and interatomic forces. For many substances, these forces are strong enough to maintain the atoms in definite ordered arrays, called crystals. Solids with little or no crystal structure are termed amorphous. [Pg.26]

Gases have weaker attractive forces between individual molecules and therefore diffuse rapidly and assume the shape of their container. Molecules can be separated by vast distances unless the gas is subjected to high pressure. Their volumes are easily affected by temperature and pressure. The behaviour of any gas is dependent on only a few general laws based upon the properties of volume, pressure and temperature as discussed in Chapter 4. [Pg.26]

The molecules of liquids are separated by relatively small distances so the attractive forces between molecules tend to hold firm within a definite volume at fixed temperature. Molecular forces also result in tlie phenomenon of interfacial tension. The repulsive forces between molecules exert a sufficiently powerful influence that volume changes caused by pressure changes can be neglected i.e. liquids are incompressible. [Pg.26]

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. [Pg.26]

Important common physical properties related to these states of matter are summarized in Table 3.3. [Pg.26]

Single crystals are the most valuable subjects for investigating the bulk properties of materials. In particular, they clearly demonstrate the conduction anisotropy (if any), and are free from grain-boundary effects. For technical utilization, however, they are usually impractical due to their unsuitable shape and size, and high cost of production. [Pg.227]

Ceramics - that is, sintered polycrystalline bodies (often containing some glass [Pg.227]


As it is now possible by choice of suitable conditions to prepare most compounds in this form, the colloid state should be considered as a physical state in which all substances can be made to exist. Many ma terials such as proteins, vegetable fibres, rubber, etc. are most stable or occur naturally in the colloidal slate. In the colloidal stale the properties of surface are all-important. [Pg.106]

U is essential to specify the physical states of the reactants and products, since there may t>e additional heat changes associated with changes in state. [Pg.201]

In the expression for heating value, it is useful to define the physical state of the motor fuel for conventional motor fuels such as gasoline, diesei fuel, and jet fuels, the liquid state is chosen most often as the reference. Nevertheless, if the material is already in its vapor state before entering the combustion system because of mechanical action like atomization or thermal effects such as preheating by exhaust gases, an increase of usefui energy resufts that is not previously taken into consideration. [Pg.184]

It is evident from the preceding material that a great deal of interest has centered on the chemical and physical state of the adsorbate. There is no reason not to expect the adsorbate to affect properties of the adsorbent. For example,... [Pg.589]

Surface electron charge density can be described in tenus of the work fiinction and the surface dipole moment can be calculated from it ( equatiou (Bl.26.30) and equation (B1.26.31)). Likewise, changes in the chemical or physical state of the surface, such as adsorption or geometric reconstruction, can be observed through a work-fimction modification. For studies related to cathodes, the work fiinction may be the most important surface parameter to be detenuined [52]. [Pg.1895]

Schemes for classifying surfactants are based upon physical properties or upon functionality. Charge is tire most prevalent physical property used in classifying surfactants. Surfactants are charged or uncharged, ionic or nonionic. Charged surfactants are furtlier classified as to whetlier tire amphipatliic portion is anionic, cationic or zwitterionic. Anotlier physical classification scheme is based upon overall size and molecular weight. Copolymeric nonionic surfactants may reach sizes corresponding to 10 000-20 000 Daltons. Physical state is anotlier important physical property, as surfactants may be obtained as crystalline solids, amoriDhous pastes or liquids under standard conditions. The number of tailgroups in a surfactant has recently become an important parameter. Many surfactants have eitlier one or two hydrocarbon tailgroups, and recent advances in surfactant science include even more complex assemblies [7, 8 and 9]. Schemes for classifying surfactants are based upon physical properties or upon functionality. Charge is tire most prevalent physical property used in classifying surfactants. Surfactants are charged or uncharged, ionic or nonionic. Charged surfactants are furtlier classified as to whetlier tire amphipatliic portion is anionic, cationic or zwitterionic. Anotlier physical classification scheme is based upon overall size and molecular weight. Copolymeric nonionic surfactants may reach sizes corresponding to 10 000-20 000 Daltons. Physical state is anotlier important physical property, as surfactants may be obtained as crystalline solids, amoriDhous pastes or liquids under standard conditions. The number of tailgroups in a surfactant has recently become an important parameter. Many surfactants have eitlier one or two hydrocarbon tailgroups, and recent advances in surfactant science include even more complex assemblies [7, 8 and 9].
Transient, or time-resolved, techniques measure tire response of a substance after a rapid perturbation. A swift kick can be provided by any means tliat suddenly moves tire system away from equilibrium—a change in reactant concentration, for instance, or tire photodissociation of a chemical bond. Kinetic properties such as rate constants and amplitudes of chemical reactions or transfonnations of physical state taking place in a material are tlien detennined by measuring tire time course of relaxation to some, possibly new, equilibrium state. Detennining how tire kinetic rate constants vary witli temperature can further yield infonnation about tire tliennodynamic properties (activation entlialpies and entropies) of transition states, tire exceedingly ephemeral species tliat he between reactants, intennediates and products in a chemical reaction. [Pg.2946]

Relaxation kinetics may be monitored in transient studies tlirough a variety of metliods, usually involving some fonn of spectroscopy. Transient teclmiques and spectrophotometry are combined in time resolved spectroscopy to provide botli tire stmctural infonnation from spectral measurements and tire dynamical infonnation from kinetic measurements that are generally needed to characterize tire mechanisms of relaxation processes. The presence and nature of kinetic intennediates, metastable chemical or physical states not present at equilibrium, may be directly examined in tliis way. [Pg.2946]

By the veiy meaning of a physical state, we must require that... [Pg.614]

It must be emphasised that the above Tables must be used with caution. The presence of a specific group cannot always be established with certainty from the presence of the absorption band, particularly in the deformation vibration region on the other hand, the absence of the appropriate absorption band indicates that the grouping is not present. The physical state in which the substance is examined may have an appreciable influence the Tables apply generally to dilute solutions in organic solvents (see Table I). [Pg.1142]

The study of the infrared spectrum of thiazole under various physical states (solid, liquid, vapor, in solution) by Sbrana et al. (202) and a similar study, extended to isotopically labeled molecules, by Davidovics et al. (203, 204), gave the symmetry properties of the main vibrations of the thiazole molecule. More recently, the calculation of the normal modes of vibration of the molecule defined a force field for it and confirmed quantitatively the preceeding assignments (205, 206). [Pg.53]

Finally, the S(CH) bending frequencies are practically independant of the physical state of the sample as are the nuclear vibration modes (Table 1-27). [Pg.61]

TABLE 1-27. INFRARED FREQUENCIES OF THIAZOLE AS A FUNCTION OF THE PHYSICAL STATE AND ASSIGNMENT... [Pg.62]

IR spectra can be recorded on a sample regardless of its physical state—solid liquid gas or dissolved m some solvent The spectrum m Eigure 13 31 was taken on the neat sample meaning the pure liquid A drop or two of hexane was placed between two sodium chloride disks through which the IR beam is passed Solids may be dis solved m a suitable solvent such as carbon tetrachloride or chloroform More commonly though a solid sample is mixed with potassium bromide and the mixture pressed into a thin wafer which is placed m the path of the IR beam... [Pg.559]

The physical state of each substance is indicated in the column headed State as crystalline solid (c), liquid (Iq), or gaseous (g). Solutions in water are listed as aqueous (aq). [Pg.532]


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