Page 27 - Curriculum Visions Dynamic Book

 The powder turns black and begins to decompose into mercury and oxygen gas.
 The mercury condenses on the cooler part of the tube, forming a mercury mirror.
 Red mercuric oxide (HgO) is heated.
amalgam: a liquid alloy of mercury with another metal. distillation: the process of separating mixtures by condensing
the vapours through cooling.
enzyme: organic catalysts in the form of proteins in the body that speed up chemical reactions. Every living cell contains hundreds of enzymes, which ensure that the processes of life continue. Should enzymes be made inoperative, such as
through mercury poisoning, then death follows.
ore: a rock containing enough of a useful substance to make mining it worthwhile.
surface tension: the force that operates on the surface of a liquid, which makes it act as though it were covered with an invisible elastic film.
vapour: the gaseous form of a substance that is normally a liquid. For example, water vapour is the gaseous form of liquid water.
Mercury vapour
If mercury is heated in a glass tube, the liquid will give off vapour. The vapour will condense back to a liquid in the upper, cooler regions of the tube, producing a mercury mirror.
The fact that mercury will vaporise readily is extremely important for metal refining. An ore is
first mixed with mercury to make an amalgam (see page 36). This separates the metal from its ore. If the amalgam is heated, the mercury vaporises, leaving the desired metal behind. Gold prospectors use mercury extensively.
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