Санкт-петербургского государственного университета высшее профессиональное образование т. А. Степанова, И. Ю. Ступина
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| Scction II
Упр. 1. Назовите значення следующих интернациональных слов: type, component, ethyl alcohol, zinc, metal, palladium, composition, really, contain, specify Упр. 2. Проверьте, помните ли вы значення следующих слов; если нет, обратитесь к словарю: just as, relationship, list, satisfy, treat, respectively Text 27 В Прочтите текст про себя (контрольное время чтения — 3 минуты). Types of Solutions Just as the variables, pressure, volume, and temperature, were used to describe tlic state or condition of pure gases, liquids, and solids, these and certain other variables must be used to describe solutions. First, some statement must be made about what chcmically important constituents arc present in the solution to be considered. A solution of ethyl alcohol (C2HjOH) and water really contains three elements: hydrogen, oxygen and carbon. However, bccausc there is a quantitative relationship (the law o f definite composition) between the amounts of carbon, hydrogen, and oxygen in ethyl alcohol, and a similar relationship between the amounts o f hydrogen and oxygen in water, the composition of the solution can be completely described by specifying only the quantities of alcohol and water wc used to prepare the solution. The substanccs used to specify the composition o f a solution arc known as components. One o f the components, usually the one which is present in greatest quantity, is callcd the solvent; any other component is callcd a solute. There arc many possible types of solute-solvent pairs to be listed later. A mixture of two gases satisfies our definition of a solution, but tlic properties of gaseous mixtures arc usually treated by Dalton's law and wc shall not consider them here. Other types of solutions that arc important arc: 1) liquid in liquid; 4) liquid in solid; 2) solid in liquid; 5) gas in solid; 3) gas in liquid; 6) solid in solid. Ex. 12. Answer the following questions: 182 O f these, the first three are common, and the last three, callcd solid solutions, occur less frequently. Mercury dissolved in zinc, hydrogen gas dissolved in palladium metal, and zinc dissolved in copper arc examples o f solutions in which liquid, gas and solid, respectively, arc dissolved in solid. Apart from their mechanical properties, solid solutions do not differ greatly from the solutions of liquids. Упр. 3. Передайте основное содержание текста в нескольких пред ложениях. Упр. 4. Какое слово в тексте означает «помимо, кроме»? Упр. 5. Найдите в тексте ответы на следующие вопросы: 1. Какие параметры использовались для описания физического состояния веществ? 2. Как определяется состав раствора? 3. Как опи сываются составные части раствора? 4. Что говорится о свойствах газовых смесей? 5. Какие типы растворов относят к твердым раство рам? 6. Чем отличаются твердые растворы от жидких? Упр. 6. Закончите следующие предложения: 1. Pressure, volume, temperature and certain other variables were used... 2. A solution of ethyl alcohol contains... 3. A solvent is... 4. A solute is... 5. The most common types of solutions arc... 6. Solid solutions occur... жүктеу/скачать 5,96 Mb. Достарыңызбен бөлісу:
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