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.

Aqua Regia

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Aqua Regia (Latin, “royal water”), mixture of concentrated hydrochloric and nitric acids, containing one part by volume of nitric acid to three parts of hydrochloric acid. Aqua regia was used by the alchemists and its name is derived from its ability to dissolve the so-called noble metals, particularly gold, which are inert to either of the acids used separately. It is still occasionally used in the chemical laboratory for dissolving gold and platinum.