Matter & Energy


Matter is composed of atoms or groups of atoms called molecules. The arrangement of particles in a material depends on the physical state of the substance. In a solid, particles form a compact structure that resists flow. Particles in a liquid have more energy than those in a solid. They can flow past one another, but they remain close. Particles in a gas have the most energy. They move rapidly and are separated from one another by relatively large distances.

Toluene

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Toluene, colorless hydrocarbon, occurring in coal tar, specific gravity 0.86, boiling point 110.6° C (231.1° F). Toluene is sometimes called toluol or methylbenzene. The name toluene reflects the way in which it was once prepared, through destructive distillation of balsam of tolu. A great deal of industrial toluene is prepared in oil refineries by the alkylation of benzene. It is used as a solvent and as a source of synthetic compounds, for example, in the production of trinitrotoluene. Prolonged breathing of toluene vapor is harmful and should be avoided.