Define the functions of the Participles. Translate the sentences

Mixtures and Compounds

Read and translate.

While translating these sentences pay special attention to the prepositions.

Model: The sampleshave already been sent for.

За образцами уже послали.

1. The new book is much spoken about. 2. These data will be often referred to. 3. The analyst has been sent for. 4. Mixtures are often experimented upon. 5. Chemical substances are worked at. 6. These data can be relied upon. 7. Mercury is often made use of.

All of the chemical substances we know may be divided into three classes: mixtures, compounds and elements. A mixture is made up of two or more substances that are not combined chemically and may be present in any proportion. Mixtures are much worked at and experimented upon.

Mixtures may be separated into components which may be either simple mixtures and hence heterogeneous, or specific, homogeneous substances. Separation may be continued until substances are obtained. Each of these resulting substances falls into one of two categories. Substances which, as a result a chemical change, can be broken down into two or more simpler chemical substances, are called compounds. Substances which, as a result of a chemical change, can be broken down into two or more simpler chemical substances, are called compounds. Compounds, as has been stated, are homogeneous and possess specific physical and chemical properties. But one of their chemical properties is the ability to decompose into simpler substances as the result of certain chemical changes.

Compounds are, therefore, complex, and they constitute by far the larger class of chemical substances.

Substances which cannot be broken down into simpler chemical substances by chemical means are called chemical elements or simply elements.

Scientific knowledge of elements, compounds and mixtures grows at a faster and faster rate. An interesting aspect of this growth is the fact that the greater our knowledge becomes the greater is our vista and consequently the more we are aware of the magnitude of the unknown.

Notes to the text:

vista– перспектива by far– гораздо

consequently – следовательно to be aware of– знать, сознавать

1. Units referred to as basic are elements. 2. Elements are referred to as basic units of matter. 3. Substances composed of two or more elements are called compounds. 4. Substances are composed of some elements combined chemically. 5. Combined together the two different substances are referred to by chemists as a compound. 6. Different substances not combined chemically are called mixtures.7. Chemical substances worked at can be divided into three classes. 8. Mixtures experimented upon are of great importance.

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