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.

Chloroform

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Chloroform, name given to trichloromethane because of its supposed relation to formic acid. A colorless liquid, half again as dense as water and of about the same viscosity, chloroform has a heavy, etherlike odor and a burning sweetness of taste, being about 40 times as sweet as cane sugar. It is almost insoluble in water, but it is freely miscible with organic solvents and is an important solvent for gums, resins, fats, elements such as sulfur and iodine, and a wide variety of organic compounds.

Chloroform may be prepared by the chlorination of ethyl alcohol or of methane, or by the action of iron and acid on carbon tetrachloride; the latter is the principal industrial method in current use.

Chloroform was first prepared in 1831 and was first used as an anesthetic in 1847 in one of the earliest experiments on surgical anesthesia. In the presence of light, however, it tends to decompose, yielding the highly poisonous compound phosgene. Even when pure, it causes fatal cardiac paralysis in about one out of 3000 cases, and so is seldom used for anesthesia.