Lesson 1 Грамматика. Различные значения it
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TEXT 5 B Physical and Chemical Properties of Substances Properties. Bodies are composed of materials such as wood, steel, cement, stone, silver, gold, lead, iron, etc. These materials may be either homogeneous or heterogeneous. A substance is defined1 as a variety of matter which has definite properties and definite composition. All samples of a substance possess the same properties and have the same composition, regardless of their source2. Every substance therefore possesses specific physical properties, such as colour, odour, density, hardness, melting point, and boiling point. Every substance also possesses definite chemical properties; these concern its transformations3 into other substances, and especially, the different kinds of substances into which it can be transformed. Water is an example of a substance; one sample of water is like all others and there is only one set of properties by which all samples of water can be described and identified. Примечания к тексту define – определять regardless of their source – независимо от их источника these concern its transformations – они связаны с его превращением Поставьте три вопроса к каждому абзацу текста и передайте содержание прочитанного на английском языке. Переведите на английский язык, пользуясь словами и словосочетаниями из предыдущих текстов: Химия изучает вещества, их состав, а также процессы и законы, по которым происходит изменение их состава. Все окружающие нас предметы состоят из веществ. Вещества состоят из одинаковых молекул и различаются по своим свойствам. Свойства веществ можно разделить на две группы: физические и химические. При изменении физических свойств состав вещества не меняется. Изменение химических свойств веществ связано с изменением их состава. LESSON 6 Грамматика. Дополнительные придаточные предложения. Различные значения that. Предтекстовые упражнения Укажите,какими союзами и союзными словами вводятся придаточные дополнительные предложения, и переведите следующие предложения на русский язык: 1. By means of this formula one can easily determine whether a given gas is lighter or heavier than air. 2. One can show experimentally that hydrogen does not support burning. 3. At the beginning of the experiment it is not known yet if the necessary data will be obtained. 4. Everybody knows how closely chemistry is connected with the progress of the world. 5. The students want to know who will deliver lectures on chemistry. 6. Newton first explained why all objects on the Earth attracted one another. Найдите придаточные предложения и переведите их на русский язык: 1. The students told their teacher they were ready to start their work. 2. The newcomer said he had come from the Far East. 3. We didn’t know you could speak German. 4. My friend thinks he can finish his work in an hour. Определите значения слова that и переведите следующие предложения на русский язык: 1. Now we know that all substances consist of atoms. 2. It was in Russia that the large-scale production of synthetic rubber was established. 3. That water is a compound was proved at the end of the 18th century. 4. The decision of the commission was that the discovery was of great importance to industry. 5. The distance that light travels in one second is 300 thousand kilometers. 6. The melting point of titanium is 2,0000 above that of aluminium. 7. The properties of metals are different from those of wood. Переведите следующие слова, не пользуясь словарем: barometer [bə'rmɪtə], character ['kærɪktə], condensation [ˌknden'seɪʃən], formula ['fɔ:mjlə], fundamental [ˌfʌndə'mentl], information [ˌɪnfə'meɪʃn], platinum ['plætɪnəm], progress ['prgres] Переведите предложения, обращая внимание на значение следующих слов и словосочетаний: effect n – действие; влияние; результат 1. The effect of heat influences the rate of many reactions. 2. Scientists study the effect of cosmic radiation upon the human body. 3. The effect of our experiment was excellent. effect v – производить; выполнять; осуществлять 1. They effected a change in the plan of their work. 2. The scientists effected the plan of their research before the time appointed. 3. They effected the isolation of a new substance. to affect v – воздействовать на Moisture affects many metals. it takes – нужно, требуется It takes energy to move a body. to mean – значить, означать Isotopes are different forms of the same element (simple type of a substance). The word “isotope” means “same place”. means n – средство; средства 1. Atoms cannot be broken down by chemical means, so it’s impossible to break up an element into simpler substances by chemical changes. 2. At present we have many means of defense against air and chemical danger. by means of – посредством One can express the composition of a compound by means of a chemical formula. Обратите внимание на ударение в следующих словах. Переведите эти слова: 'element – ele'mentary, 'atom – a'tomic, 'molecule – mo'lecular, 'oxidize – oxi'dation, re'duce – re'duction, e'lectric – elec'tricity, 'metal – me'tallic, 'stable – sta'bility, 'compound – com'pound, 'transport – trans'port Запомните произношение следующих слов: necessary ['nesɪsərɪ], acquainted [ə'kweɪntɪd], essential ['senʃl], lustrous ['lʌstrəs] TEXT 6 A Changes of Matter None of the properties of a substance is more important to the chemist than the changes the substance can undergo, and no knowledge about the substance is more important than information concerning the conditions that are necessary to effect these changes. We know of many changes that occur continually around us and that alter greatly the different forms of matter we are acquainted with. These changes are either physical or chemical. Chemical Changes Chemical changes are those matter changes in which a change of composition takes place. Such changes are permanent, i.e. they cannot be undone1 by simple application of some physical means, such as heating, cooling, or evaporation, but the new substance, or substances formed persist2 unless they are subjected to another chemical change. In determining whether a given matter change is a physical or chemical change, the essential question is whether or not one or more substances, with properties different from those of the substance or substances existing before the change, have been formed. Thus iron is a hard, grayish, lustrous substance but when it is left exposed to moist air it is slowly transformed into a red crumble material (iron rust) quite different in properties from the original iron. A chemical change has, therefore, taken place; the change in properties is the outward indication of the formation of a different substance. The new, reddish substance will not become iron again when it is allowed to stand, although the iron can be obtained from it, if it is subjected to the right conditions. It took a chemical change to convert iron into iron rust, and another chemical change would be necessary3 to turn the iron rust into iron again. In the burning of wood a chemical change takes place, since the wood disappears and new substances (gases, ash, etc.) appear which are very different in their properties from wood. Примечания к тексту they cannot be undone – они не могут быть уничтожены substances formed persist – образовавшиеся вещества сохраняются and another chemical change would be necessary – и потребовалось бы другое химическое изменение Запомните следующие слова и словосочетания: after, appear, around, cooling, effect, essential, gray, greatly, hard, heating, indication, i.e., lustrous, moist, occur, outward, permanent, subject to, transform, undergo, wood Упражнения Выпишите из текста: а) дополнительные придаточные предложения; б) предложения, в которых встречается that, и определите его значения; в) бессоюзные определительные придаточные предложения. Поставьте вопросы к выделенным словам: 1. When iron is exposed to moist air it is slowly transformed into iron rust. 2. In the burning of wood a chemical change takes place. 3. During the burning wood disappears and new substances appear. Переведите следующие предложения на русский язык, обращая внимание на значение that: 1. Some properties of air are similar to those of water. 2. We know that air has pressure. 3. A barometer is an instrument that measures air pressure. 4. The production of ozone requires that a large quantity of energy be absorbed. 5. It is the law of conservation of mass that makes possible the writing of chemical equation. 6. The amount of heat liberated by slow oxidation is the same as that liberated by rapid combustion. 7. That water is a compound was proved at the end of the 18th century. Определите по суффиксам, к какой части речи относятся данные слова, и переведите их на русский язык: property, substance, chemist, information, important, necessary, continually, chemical, composition, different, essential, grayish, lustrous Переведите следующие слова, обращая внимание на суффикс -ish: reddish, bluish, yellowish, grayish Сгруппируйте синонимы и переведите их на русский язык: important, moist, to permit, to occur, right, to alter, to convert, essential, to change, since, to allow, to take place, because, wet, proper Сгруппируйте антонимы и переведите их на русский язык: necessary, to disappear, greatly, similar, heating, moist, slowly, to allow, right, to appear, to prohibit, rapidly, dry, cooling, to a little extent, different, wrong, unnecessary Дайте недостающие основные формы следующих глаголов: to undergo, to take, to give, to leave, to become Заполните пропуски следующими словами и словосочетаниями: to turn, takes place, whether, unless, in time, to subject, to take 1. Chemical changes are those matter changes in which a change of composition … . 2. It is essential … you finish your experiment … . 3. This substance will not change its properties … you … it to a chemical change. 4. It … a chemical change to convert iron into iron rust. 5. A chemical change is necessary ... the iron rust into iron again. Ответьте на следующие вопросы: 1. What changes of matter do we call chemical changes? 2. What is the essential question in determining whether a matter change is a physical or a chemical one? 3. What are the properties of iron? 4. What happens if iron is left exposed to moist air? 5. Why do we say that in the burning of wood a chemical change takes place? Выберите правильный английский вариант перевода:
Прочитайте текст 6 В, не пользуясь словарем: TEXT 6 B Physical changes When physical changes occur, some of the properties of a substance may be altered for a time, but no new substances are formed. The following are the examples of a physical change: 1) the melting of ice and the condensation of steam; 2) the mixing of sugar with water to form a solution; 3) the change observed when a platinum wire1 is heated to redness. In each of these there is a change in properties. Thus, a liquid is produced from a solid when ice melts, and a gas is changed into a liquid when steam condenses. When sugar dissolves, it, too, changes from the solid to the liquid state. The platinum wire changes, when heated2, from a silvery lustrous metal that reflects light to one that emits3 light. But there is no alternation of the fundamental character of any of the substances during these changes. Sugar dissolved in water retains4 its original properties and only forms a mixture from which it is readily obtained again in its crystalline form by allowing the water to evaporate. |