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.

Antifreeze

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Antifreeze, chemical substance added to a liquid to lower its freezing point. It prevents the freezing of the coolants used in airplane, automobile, and tractor engines, in refrigeration liquids, and in snow-melting and deicing agents.

The ideal antifreeze should be chemically stable, be miscible in the coolant, have low viscosity and electrical conductivity and a high boiling point, be noncorrosive, and have good heat-transfer properties. The most widely used antifreeze materials in automotive engines today are methyl alcohol, ethyl alcohol, and ethylene glycol; most of them contain a phosphate, nitrate, or other anticorrosive agent.