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
| Scction II
Упр. 1. Назовите значения следующих интернациональных слов: catalyst, speed, specific, action, laboratory, industry, biological, system, manufacture, margarine, regulate, enzyme, majority, practically, phenomenon, material, catalysis, elementary, regenerate Упр. 2. Определите значения выделенных слов по контексту. 1. Among the factors that alter the rate of a chemical reaction arc temperature, concentration, etc. 2. Sometimes, when the work is especially difficult, wc ask for aid. 3. A particular property o f a catalyst is that it is not consumed in the reaction. 4. When a compound has some quantity of a foreign substancc, it cannot be considered pure. Слова к тексту: digestion— переваривание (nuu/u); augment— увеличивать; provide— обеспечивать 146 Text 21 В Прочтите текст про себя (контрольное время чтения— 2,5 минуты). A Catalyst A catalyst is a substancc that alters the speed of a chcmical reaction without itself undergoing any chcmical changc, usually only a small quantity of it is required. Catalysts arc usually specific in action; thus, a catalyst for one reaction is more often than not useless for any other reaction. They arc extremely important substances not only in the laboratory but also in chcmical industry and in biological systems. Thus, the manufacture of sulphuric acid, ammonia and margarine involves the application of catalysts, the most of the chcmical reactions that occur in our bodies arc regulated by these substances. In biological systems substances callcd enzymes function as catalysts, c. g., specific enzymes arc used to aid the digestion of food in the stomach. Chemists have discovered the great majority o f reactions that procccd without catalysts. But there are almost innumerable other reactions that cannot be practically effected without a catalyst. The phenomenon in which a relatively small amount of a foreign material, callcd a catalyst, augments the rate of a chcmical reaction is callcd catalysis. A catalyst provides the possibility of new elementary processes taking place, but it is not consumed during the reaction. If wc cannot have it regenerated, there is no catalysis. Упр. 3. Передайте основное содержание текста в нескольких пред ложениях. Упр. 4. Составьте план текста. Упр. 5. Прочтите предложения и скажите, соответствуют лн они содержанию текста. Если нет, исправьте их. 1. A catalyst is a substancc that changes the rate of a chcmical reaction. 2. A catalyst undergoes little changcs in the reaction. 3. Catalysts arc important both in laboratory and in industry. 4. Enzymes arc catalysts for biological systems. 5. No reaction can procccd without a catalyst. Упр. б. Найдите в тексте предложения, гас перечислены отличитель ные свойства катализа как явления, и переведите их на русский язык. жүктеу/скачать 5,96 Mb. Достарыңызбен бөлісу:
|