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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
Highly toxic chemicals
Less toxic 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
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
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.
- Spring '07