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COLLOID CHEMISTRY

 

 

TEXT A

 

Pre-Reading Task

What do you know about colloid chemistry?

 

Research in colloid chemistry is becoming increasingly important in various branches of pure chemistry, industry, medicine and many other fields. Adsorption, dialysis and coagulation are important in preparative chemistry, in analytical chemistry (co-precipitation, washing of precipitates, filtration problems, chromatographic adsorption analyses), in soil chemistry, in clinical work and in the preparation of pharmaceutical mixtures such as emulsions. Colloid chemical approaches are very important in dealing with numerous technical and industrial problems.

Colloid science is an interdisciplinary intersection of branches of chemistry, physics, nanoscience and other fields dealing with colloids, heterogeneous systems consisting of a mechanical mixture of particles between 1 nm and 1000 nm dispersed in a continuous medium. A disperse system denotes any homogeneous medium containing dispersed entities of any size and state. Usually disperse systems are solutions of various types.

 

Why is the research in colloid chemistry becoming increasingly important?

In what field of chemistry are colloid chemical problems encountered?

 

Here are several definitions of the key terms you are going to meet in the text. Which of them are not correct?

1. A mixture is a collection of two or more pure substances physically mixed together.

2. A suspension is a mixture that appears uniform while being stirred, but separates into different phases when agitation ceases.

3. A solution is defined as a heterogeneous mixture of two or more chemical substances.

4. A solvent is any substance which allows other substances to dissolve in it.

5. A saturated solution is the one containing the standard amount of solute specified by the solubility at a given temperature.

6. The solubility of a chemical substance is a physical property referring to the ability of that substance, called the solute, to dissolve in a solvent.

Give your own definitions of these terms.

Read and study these words and word combinations:

to prevent препятствовать, предотвращать

to bring about вызывать, влечь за собой

to come to rest приходить в состояние покоя

it is common knowledge общеизвестно, что

to the naked eye невооруженным глазом

It is customary to speak принято говорить

as a matter of convenience для удобства

to be intended to предназначаться для, иметь целью

to be at the end заканчиваться

to be in operation действовать, идти, развиваться

in reality в действительности

no longer больше не

as long as пока

 


Date: 2015-01-29; view: 1196


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