safety-in-academic-chemistry-laboratories-students

The answer classification the hazardous

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Unformatted text preview: know the hazardous characteristics of so many different chemicals? The answer: classification. The hazardous characteristics of all chemicals can be sorted into just a few classes. The important classes to consider in accident prevention include those listed in the box. Class Examples Oxidizing agents Reducing agents Corrosive chemicals Water-reactive chemicals Air-reactive chemicals Highly toxic chemicals Less toxic chemicals Self-reactive chemicals Incompatible pairs* Nitrates, permanganates, chromates Hydrogen, carbon, hydrocarbons, organic acids Strong and some weak acids and bases, halogens Alkali metals, some hydrides, phosphides, carbides Alkali metals Carcinogens, cyanides, phenol Ethanol, n-hexane, acetic acid Picric acid, TNT, diazo compounds Acid vs base, oxidizing agent vs reducing agent *Appendix 2 lists a few examples of incompatible pairs of compounds, and examples of pairs of compounds that, if allowed to react with each other, will produce harmful toxic products. For a complete list of all such known pair combinations, see Bretherick’s Handbook of Reactive Chemical Hazards; Urben, P. G.; 6th ed.; ButterworthHeinemann: London, 2000; book and CD-ROM. Solvents and Their Hazards Of course, water is the most common solvent. As noted previously, many chemicals can react with water, some of them violently. Organic solvents (e.g., acetone, hexane, petroleum ether, trichloroethylene) are also often used, even though they present flammability hazards. It is interesting to note that a flammable liquid itself cannot burn; it is the vapor from the liquid that burns. The rate at which a liquid produces flammable vapors depends on its rate of vaporization, which increases as the temperature increases. Consequently, a flammable liquid is more hazardous at elevated temperatures than at normal temperatures. All flammable liquids and solids must be kept away from oxidizers and from inadvertent contact with ignition sources. Some organic solvents can penetrate intact skin. When in contact...
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This document was uploaded on 02/27/2014 for the course PHYS 1B at UCSD.

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