Chemical substances liquids

Flammable Any chemical substance, liquid or solid, that has a flash point of 100°F or below any solid that can sustain fire and ignite readily any material that can be ignited easily and will burn rapidly Flash point The temperature at which a liquid will generate sufficient vapors to promote combustion. Generally, the lower the flash point is, the greater the danger of combustion is... 

The phase rule is a mathematical expression that describes the behavior of chemical systems in equilibrium. A chemical system is any combination of chemical substances. The substances exist as gas, liquid, or solid phases. The phase rule applies only to systems, called heterogeneous systems, in which two or more distinct phases are in equilibrium. A system cannot contain more than one gas phase, but can contain any number of liquid and solid phases. An alloy of copper and nickel, for example, contains two solid phases. The rule makes possible the simple correlation of very large quantities of physical data and limited prediction of the behavior of chemical systems. It is used particularly in alloy preparation, in chemical engineering, and in geology. 

The thermodynamic properties of a chemical substance are dependent upon its state and, therefore, it is important to indicate conditions when writing chemical reactions. For example, in the burning of methane to form carbon dioxide and water, it is important to specify whether each reactant and product are solid, liquid, or gaseous since different changes in the thermodynamic property will occur depending upon the state of each substance. Thus, different volume and energy changes occur in the reactions... 

We developed the concept of the mole In terms of pure chemical substances, but many chemical reactions take place In solution. To treat solution reactions quantitatively, we need ways to apply the mole concept to solutions. A substance used to dissolve solutes Is a solvent, and a pure substance dissolved In solution Is a solute. Most of the time, the solvent Is a liquid and Is present In much larger quantities than any solutes. 

The combustion of a chemical substance takes place in the gaseous phase except with metals and metalloids where combustion takes place in the solid phase. This impiies that a soiid or a liquid inflammable chemical has the ability to vapourise in order to buiid an inflammable vapour-air mixture. The two indicative parameters are the boiling point and, most important, the vapour pressure of the liquid. 

Municipal waste (MW) Always relevant except intermediates only use in processing aids Articles waste for recycling (RW -solid) Relevant if substance is induded in aifides of glass, paper, plastics, rubber, metal, construction material or in specific articles (cars. EEE etc ) Hazardous waste (HW) Substances as such or in chemical products, liquid wastes for recycling... 

Homeopathic remedies are very low dose therapeutical preparations produced from different source materials/substances (e.g. extracts from plants or animal tissues, animal secretions, minerals or chemical substances). The source substances are processed and diluted with water under defined conditions. The diluted homeopathic remedy (also called preparation) is then applied to the animal orally either as a liquid or after application of the remedy onto... 

Chemical Substance A substance usually associated with some description of its toxicity or exposure hazard, including solids, liquids, mists, vapors, fumes, gases, and particulate aerosols. Exposure, via inhalation, ingestion, or contacts with skin or eyes, may cause toxic effects, usually in a dose-dependent manner. 

As the mole fraction of A in the mixture iucreases toward uuity, the secoud term iu Eq. (2.17) teuds toward zero, aud the chemical poteutial of A teuds toward the standard chemical potential, Pa = G, the molar Gibbs euergy (or chemical poteutial) of A iu the realizable standard state of pure A, in the sense that pure liquid A is a known chemical substance. A similar equation holds for the component B. 

Preventing exposure to hazardous industrial chemicals is a primary concern at industrial sites. Most sites contain a variety of chemical substances in gaseous, liquid, or solid form. These substances can enter the unprotected body by inhalation, skin absorption, ingestion, or through a puncture wound (injection). A contaminant can cause damage at the point of contact or can act systemically, causing a toxic effect at a part of the body distant from the point of initial contact. 

LIQUID-PHASE BEHAVIOR. The liquid phase contains dissolved substances and contacts the solid phase. For our purposes, the liquid phase is used synonymously with aqueous phase , and all processes discussed in this section take place in aqueous solutions. The dissolved monomers of the solid phase are formed in equilibrium with their uncomplexed components. Such components may be uncomplexed ions (which are charged atoms or molecules) free in solution or ionic complexes in equilibrium with dissociated ions. Concentrations of the uncomplexed ions, therefore, depend upon the concentrations of all chemical substances competing for binding interactions with them. Each complex-ation reaction is defined by either a solution equilibrium constant ... 

Hexanone, also known as methyl n-butyl ketone or MBK, is a clear, colorless liquid with a somewhat sharp odor. The liquid form can easily evaporate into the air as a vapor. It is a waste product of wood pulping, coal gasification, and oil shale operations. 2-Hexanone was formerly used in paint and paint thinner and in various chemical substances. However, since it was found to have harmful health effects, it is no longer made in the United States, and its uses have been restricted. There are no known major natural sources of 2-hexanone in the environment. When 2-hexanone is released to rivers or lakes, it dissolves very easily, and it may evaporate into the air in a few days. We do not know if 2-hexanone binds to soil. When 2-hexanone is released to the water, air, or soil, it is probably broken down into smaller products, possibly within a few days. 

The other major route of chemical hazards to plant workers is penetration through the skin, which has a surface area of about 1.8 m for a male adult, and is lined with a tough horny layer of densely packed cells without nuclei. So the skin is reasonably impervious to the penetration of chemical substances, and penetration depends on the lipid solubility of the compound, where the diffusion speed is inversely related to molecular weight. Skin penetration hazard becomes relatively more important than breathing for high boiling point liquids, which have lower vapor pressures. 

Ammonia causes intense irritation of eyes, nose and respiratory tract which can lead to tears, respiratory distress, chest pain, and pulmonary edema. A few minutes exposure to 3,000 ppm can cause severe blistering of skin, lung edema, and asphyxia which can lead to death (Patnaik, P. 1992. A Comprehensive Guide to the Hazardous Properties of Chemical Substances, p. 304. New York, Van Nostrand Reinhold). Contact with liquid ammonia can cause serious blistering and destruction of skin tissues. LC50 inhalation (mouse) 4,200 ppm/hr. 

Very simply, the two chemical substances involved, sodium chromate and lead nitrate, have exchanged partners to make two new substances, sodium nitrate, which remains in the solution, and lead chromate. This settles at the bottom of the liquid as a very fine yellow powder, chrome yellow. 

Melting point describing the temperature at which the solid to liquid transition takes place is one of the main characteristics of chemical substances. When heat is supplied to a crystalline species its temperature usually rises until it starts to melt. This temperature corresponding to the melting point is maintained until all the substance is liquified. During this process the long-range order of the crystalline solid is destroyed. Simultaneously anisotropy of the crystal, that is, a dependence of its optical and some other properties on the direction of, for... 

Acaricide The name of a chemical pesticide used to control spiders, ticks, mites miticide. Accelerant A chemical substance used to initiate or promote fire. Flammable liquids may be referred to as accelerants. 

Naphtha Various volatile and often flammable liquid hydrocarbon mixtures used as solvents and diluents consists mainly of hydrocarbons with higher boiling point than gasolines and lower boiling point than kerosene principal component of chemical dispersants used prior to 1970. Naphthenes Class of hydrocarbons with similar physical and chemical properties to alkanes insoluble in water, generally boil at 10-20°C higher than corresponding carbon number alkanes. Narcosis Stupor or unconsciousness produced by chemical substances. 

One of the most effective methods for evaluating the purity of chemical substances is that involving determination of the freezing point, with appropriate observation of the temperature of the liquid-solid equilibrium as a function of the fraction of sample frozen or melted. 

Fractional solidification and its applications to obtaining ultrapure chemical substances, has been treated in detail in Fractional Solidification by M.Zief and W.R.Wilcox eds, Edward Arnold Inc, London 1967, and Purification of Inorganic and Organic Materials by M.Zief, Marcel Dekker Inc, New York 1969. These monographs should be consulted for discussion of the basic principles of solid-liquid processes such as zone melting, progressive freezing and column crystallisation, laboratory apparatus and industrial scale equipment, and examples of applications. These include the removal of cyclohexane from benzene, and the purification of aromatic amines, dienes and naphthalene. 

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