Text 6. Crystallization

Vocabulary

geometrical solid геометрическое тело

made by a natural process образующийся в естественных условиях

to absorb поглощать

to unite chemically вступать в химическое соединение

water of crystallization кристаллизационная вода

for example например

washing soda стиральная сода

to give up отдавать

to expose подвергать (действию)

to be reduced to powder превратиться в порошок

efflorescent выветривающийся

efflorescence выветривание

What is a crystal?

A crystal is a geometrical solid made by a natural process. Many substances absorb water from solutions when they crystallize; that is, they unite chemically with a definite proportion of water.

The water with which any substance unites during the process of crystallization is called the water of crystallization.

Certain crystal substances, for example, washing soda, give up their water of crystallization when they are exposed to air; they are then reduced to powder. Substances that have this property are called efflorescent, and the process is called efflorescence.

Text 7. Deliquescence

Vocabulary

deliquescence расплывание

moisture влага

impurities примеси

table salt поваренная соль

to tend иметь тенденцию

to solidify твердеть

opening отверстие

salt shaker солонка

to clog закупориваться

damp влажный

to become wet стать влажным

to dissolve растворяться

Certain other substances absorb moisture from the air when they are exposed to it; these are said to be deliquescent. The impurities often present in common table salt are typical of this class of substances. Because these impurities tend to solidify upon absorbing moisture from the air the openings of a salt shaker clog during damp weather.

A substance that absorbs moisture from the air and becomes wet or dissolves in the moisture, is called deliquescent.

Text 8. Suspensions

A

Vocabulary

suspension суспензия

watery водный

to state утверждать, констатировать

molecule молекула

with the naked eye невооруженным глазом

to distinguish различать

to travel проходить

In explaining the watery solutions of sugar, it has been stated that the water of such solutions divides the sugar into particles, called molecules, so small that they cannot be seen with the naked eye. These molecules are distinguished by the great speed at which they travel. Molecules, which are found in all substances, travel fastest in gases, less rapidly in liquids, and very slowly in solids.

В

Vocabulary

recently недавне

to believe верить, считать

have come to пришли к тому

mixture смесь

to behave вести себя

to combine соединяться)

solvent растворитель

solute растворенное вещества

true solution идеальный раствор

Scientists have recently come to believe that molecules in solutions and in liquid mixtures behave very much as they behave in gases, liquids, and solids. For instance, when two substances, such as sugar and water, are combined by dissolving, the particles of the solvent divide the particles of the solute, and the two kinds of particles then mix freely. This is a true solution.

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