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.

Aliphatic Compounds

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Aliphatic Compounds, large class of organic molecules consisting essentially of straight or branched chains of carbon atoms. Aliphatic compounds include the alkanes, alkenes, and alkynes and their derivatives. The other major class of organic molecules, aromatic compounds, forms closed ring structures.