Практикалық сабақтарының тақырыптары мен мазмұны Practical assignment №1
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chemistry (1)
- Бұл бет үшін навигация:
- ION EXCHANGE METHODS IN ANALYTICAL CHEMISTRY
- NOTES AND COMMENTARY 1. by "ion exchange" we mean
- CHROMATOGRAPHY AND ION EXCHANGE TECHNIQUE
| NOTES AND COMMENTARY
are built around two processes – базируются на двух процессах mechanized setting - механическое осаждение the process of passing … through – процесс пропускания … через depends upon – зависит revolutions per minute – обороты в минуту WORDPERFECT Vocabulary: Drill Exercises Terminology Dictionary: Study the chemical terms in the texts above and make a list of them in your vocabulary copybook ION EXCHANGE METHODS IN ANALYTICAL CHEMISTRY Ion exchange is now one of the recognized processes of chemical engineering. It has been applied to the separation processes of quantitative analysis. General Principles. By ion exchange we mean the exchange of ions of like sign between a solution and a solid insoluble body in contact with it. For such an exchange to be possible, the solid must contain ions of its own. The solid (called the ion exchanger) must have an open, permeable molecular structure, so that ions and solvent molecules can move freely in and out. Many substances, both natural and artificial, have ion exchanging properties. In analytical work we are primarily interested in the synthetic organic exchangers. These have a high capacity for holding ions and they are not broken down by acids or alkalies, they have a relatively simple composition. NOTES AND COMMENTARY 1. by "ion exchange" we mean - под ионным обменом мы подразумеваем 2. of like sign - одноименные по знаку 3. for such exchange to be possible – чтобы осуществить этот обмен 4. of it own - свои собственные 5. can move freely in and out - могут свободно входить и выходить CHROMATOGRAPHY AND ION EXCHANGE TECHNIQUE Chromatography is a method of chemical analysis based upon the selective absorption and partial fractionation of various substances by certain suitable materials. The method is simple and requires a minimum of special equipment. The technique consists of pouring a solution through a column containing a suitable adsorbing material. A selective developing agent is then passed through the column and the different substances in the solution are spread down the column into layers visibly separated from one another, provided the substances are colored. In the case of colorless substances, the layers of the different substances may be located by the use of ultra-violet light or by chemical tests. This method was first described by the Russian botanist Tswett, in 1906. Tswett was engaged in the extraction and purifictaion of plant pigments. Methods of chromatography have been applied to the separation of the rare earths and a number of procedures, based on chromatography techniques, have been developed for the separation of the inorganic cations and anions. жүктеу/скачать 64,23 Kb. Достарыңызбен бөлісу:
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