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.

Camphor

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Camphor, volatile, white, crystalline compound, with a characteristic aromatic odor. Ordinary camphor is obtained from the camphor tree, Cinnamomum camphora, which grows in Asia and Brazil. The camphor is distilled by steaming chips of the root, stem, or bark. The leaves of certain plants, such as tansy and feverfew, contain a second form of camphor, which is not used commercially. A racemic form is present in the oil of an Asian chrysanthemum and is also produced synthetically for most commercial uses. Camphor is used in the manufacture of celluloid and explosives and medicinally in liniments and other preparations for its mild antiseptic and anesthetic qualities. It is poisonous if ingested in large amounts.

Camphor is insoluble in water, soluble in organic solvents, and melts at 176° C (349° F) and boils at 209° C (405° F).