Санкт-петербургского государственного университета высшее профессиональное образование т. А. Степанова, И. Ю. Ступина
жүктеу/скачать 5,96 Mb. Pdf көрінісі
|
1stepanova t a english for chemists
| Section П
Упр. 1 . Прочтите заглавие текста 8 В. О чем, по вашему мнению, будет идти речь в этом тексте? Упр. 2. Назовите значения следующих интернациональных слов: metal, sclcnidc, proportion, material, action, chlorine, permanganate, cadmium, cobalt, nickel, zinc, product, process, contain Упр. 3. Определите значения выделенных слов по контексту. Сино нимы в скобках помогут вам. 1. The atomic weight of selenium is approximately (about) 79.2. When H 2 SO 4 is to be diluted with water, it must be poured into an excess (greater amount) of water. 3. Some reactions with conccntratcd sulphuric acid proceed quickly when they arc heated. 4. When sclcnious acid is treated with (actcd upon by) chlorine, selenic acid is produced. 5. When hydrogen sclcnidc forms, it bubbles (passes) into the liquids in the various bottles (containers for liquids). 6 . The symbols Pb, Си, K, As and Sb stand for lead, copper,potassium, arsenic and antimony. 8 . We obtained the product somewhat (to some extent) heavier than in the previous reaction. Слова к тексту: grind — измельчать; powder — порошок; mortar — ступа; dust — пыль; dry — сухой; vigorously — бурно; remove — удалять; lump — ку сок; transfer — перемещать; flask — колба; connect — соединять; flue — газоход 60 Text 8 В Прочтите текст про себя (контрольное время чтения — 5 минут). Selenium Compounds The element (selenium) can combine with the metals, just as sulphur can, forming sclenidcs. Let us grind some selenium to powder in a mortar. After that, wc should take 10 grams of this powder and grind it with 7 grams of iron dust, a proportion o f 80 and 56, the approximate atomic weight ratio of the two elements. Then, wc must pour the well-mixed material into a dry test-tube and heat it. Ferrous scicnidc is formed, the action proceeds somewhat less vigorously than that between iron and sulphur. When the tube has cooled somewhat, wc can break it open and remove a grey-black product which much resembles ferrous sulphide. Selenium will unite similarly with zinc and with other metals such as coppcr and lead. Selenium dioxide may be formed by the combustion of the element. The dioxide is white and can dissolve readily in water to form selenious acid just as sulphur dioxide dissolves to form sulphurous acid: HjO + ScO; — > H’ScOj. When selenious acid is treated with chlorine or potassium perman ganate, sclenic acid is produced; the proccss, of course, can be callcd oxidation, the reaction proceeds just as it does with sulphurous acid. Small lumps of ferrous selenidc arc transferred to a small flask connected to a train of bottles containing solutions o f a number of different metallic salts, for example, those of cadmium, cobalt, nickel, arsenic, and antimony. Any excess of gas which may escape is led into the flue. Add some hydrochloric or sulphuric acid to the material in the flask, and presently hydrogen selenidc forms and bubbles into the liquids in the various bottles. Various selcnidcs can be formed. Упр. 4. Действительно ли текст 8 В содержит ту информации», кото рую вы ожидали в нем найти? Скажите, что было для вас новым. Упр. 5. Разделите текст на тематические части и озаглавьте каж дую часть. Упр. б. Скажите, что говорится в тексте: 1 ) о способности селена реагировать с металлами; 2 ) о реакции се лена с железом; 3) об образовании диоксида селена; 4) об образовании селенистой кислоты; 5) о получении селеновой кислоты. Упр. 7. Найдите в тексте отрывок, гае описывается получение селс- нида водорода; переведите его на русский язык. 61 |