Санкт-петербургского государственного университета высшее профессиональное образование т. А. Степанова, И. Ю. Ступина
жүктеу/скачать 5,96 Mb. Pdf көрінісі
|
| Section II
Упр. 1. Назовите значения следующих интернациональных слов: component, ion, metal, ocean, complex, organic, organism, coursc, plasma, extensively, correlate, universal, barium, sulphate, milligram, litre, quartz, extremely, cellulose Упр. 2. Определите значения выделенных слов по контексту. 1. The ability of water to dissolve many substanccs is one o f its unique properties. 2. Heat and light arc usually evolved during combustion. 3. A substancc that is dissolved is callcd a solute. 4. Water is widely used both in industry and in laboratory. 5. If a solution of NaCl is evaporated to dryness, white crystals appear in the glass. 6. If a solution is saturated, no more solute can be dissolved. Слова к текст}*: environment — окружающая среда; tissue — ткань; fluid — жидкость; blood — кровь; cell — клетка; imperceptible — незаметный, незначитель ный; vessel — сосуд; eventually — в конце концов; merely — просто; exceedingly — чрезвычайно 165 Text 24 В Прочтите текст про себя (контрольное время ••тения — 4 минуты). Water One of the most striking properties of water is its ability to dissolve many substanccs, forming aqueous solutions. Solutions arc very important kinds of matter — important for industry and for life. The ocean is an aqueous solution that contains thousands of components: ions of the metals and non-metals, complcx organic ions, many different organic substanccs. It was in this solution that the first living organisms developed, and it was from it that they obtained the ions and molcculcs needed for their growth and life. In the course of time organisms that were evolved could leave this aqueous environment, and move out onto the land and into the air. They achieved this ability by carrying the aqueous solution with them, as tissue fluid, blood plasma, and intraccllular fluids containing the necessary supply of ions and molccules. The properties of solution have been extensively studied, and it has been found that they can be correlated in large part by some simple laws. Water not only is the most widely used of all solvents, but also, of all liquids, it most nearly approaches being the “universal solvent”. Every substancc is probably soluble in water to some extent, although in many eases the solubility is so small that it is almost impcrscptiblc. Thus, a saturated solution of barium sulphate contains less than a quarter of a milligram of solute per litre, and the solubility of silicon dioxide (quartz)— is even smaller than this. Yet, water that is allowed to remain for a long time in a quartz vessel must eventually bccomc saturated with quartz; a saturated solution of this substancc is so extremely dilute, however, that many litres of it would have to be evaporated to dryness in order to yield a visible residue. Such substanccs as barium sulphate, silver chloride, quartz, glass, mercury, and ccllulosc arc usually considered as “insoluble” in water; but this term, it must be remembered, is merely a relative one, and it would be more accuratc to say that their solubility is exceedingly small. Упр. 3. Передайте основное содержание текста в нескольких пред ложениях. Упр. 4. Составьте план текста. Упр. 5. Прочтите предложения н скажите, соответствуют ли они со держанию текста. Если нет, исправьте их. 1. Water can dissolve a great number o f substanccs. 2. Solutions arc important in industry, but not in life. 3. A lot of components are dissolved in the ocean water. 4. The first living organisms developed in water and on the land and then moved into the air. 5. There arc no laws common to all the solutions and the properties of cach solution arc studied separately. 6. Every substancc is soluble in water to some extent. 166 Упр. б. Найдите в тексте и переведите на русский язык предложе ния с описанием того, как ведут себя в воде вещества, которые счита ются практически нерастворимыми. жүктеу/скачать 5,96 Mb. Достарыңызбен бөлісу:
|