3 Part One. The Predicate

Liquids and Solutions
Solids and gases represent the extreme states of behaviour of molecules. The liquid state can be thought o f as an intermediate condition in which some of the properties found in cither solids or gases are displayed. Liquids, like gases are isotropic and flow readily under applied stress, but like solids, they are dense, relatively incompressible, and have properties that are largely determined by the nature and strength of intcrmolecular forces. With rcspect to molecular order, liquids are substances considered to be intermediate between solids and gases. The fact that liquids are isotropic tells us immediately that they do not have the extended latticc structure and long-range order of solids. Yet, the density o f a liquid is generally only 10% less than that of its solid phase; this must mean that the molccules in a liquid are packcd together with some regularity, and do not exhibit the complete chaos associated with molecules in the gas phase.

One of the most important properties o f liquids is their ability of acting as solvents. In the first place, liquid solutions provide an extremely convenient means of bringing together carefully measured amounts of reagents and of allowing them to react in a controlled manner. Sccond, the nature of the reactions which proceed and the speed at which they occur can be greatly influenced by the properties o f the liquid solvent medium.

Finally, the physical properties of solutions are interesting and important, because they can be used to determine molecular weights of dissolved substances and to study the nature and strength of forces between solvent and solute molecules.

One o f the most engaging and absorbing features of the study of chemistry is the attempt to explain the behaviour of bulk matter in terms of molecular properties. Therefore, it is important to outline a molecular picture which will help us to understand and relate phenomena associated with the liquid state.

Words and Word-Combinations to Be Memorized

ability, absorb, bulk, complete, convenient, display, engage, generally, intermediate, intcrmolecular, lattice, a means, outline, reagent, range, with respect to, solute, strength

Ex. 5. Give the Uzbek equivalents for the following:

think of, display some properties, dense, intcrmolecular forces, with respect to, immediately, the lattice structure, the long-range order, mean, be packed together, provide a means of, carefully measured, procccd, finally, because, the behaviour o f bulk matter, outline a picture, be associated with, the strength of forces

Ex. 6. Give the English equivalents for the following:

molekulalarning xatti-harakati, suyuqlik holati, yoki ... yoki ... asosan molekulalarning joylashish tartibi, 10% kamroq (ko'proq) o'rtasida suyuqlik zichligi, hal qiluvchi sifatida harakat qilish, ma'lum bir tezlikda harakat qilish qobiliyatiga ega bo'lgan oraliq pozitsiyani egallaydi. katta ta'sir, eritmalarning fizik xossalari, atom og'irligini, eriydigan, eruvchan moddalarni aniqlang

Ex. 7. Fill in the blanks with articles where necessary.

1 liquid state can be thought o f as intermediate condition between... solids and gases. 2 .... properties of liquids are determined by ... nature and strength o f ... intcrmolecular forces. 3— density o f ... liquid is generally only 10% less than that o f ... solid. 4. Their ability of acting as ... solvents is one o f ... most important properties o f ... liquids. 5. It is important to outline ... molecular picture o f ... liquid state.

Ex. 8. Give synonyms for the following:

think of, display, under stress, largely, immediately, little, allow, influence, feature, explain

Ex. 9. Give antonyms for the following:

incompressible, extend, long-range, less, convenient, be influenced by, most important

Ex. 10. Translate the sentences into Uzbek.

1. One should follow the proceeding reaction very carefully.2. Selenium, an element belonging to the sulphur group, is as much non- metal as metal. 3. Many factors mentioned determine the reaction rate.4. There is a striking resemblance between some elements. 5. St. Petersburg University has its own publishing house. 6. The boiling point of water is accepted to be 100°C. 7. Some objections were found to the Arrhenius theory long believed to be true. 8. The most striking thing about hydrogen is its extreme lightness. 9. An acid is defined as a compound or an ion capable o f liberating a proton. 10. Two or more atoms having identical nuclear charges but different numbers o f Acutrons are said to be isotopes. 11. Ores containing as little as 2 per cent or even less of copper or nickel are worth mining. 12. Bond formation involving elements toward the middle of the periodic tabic occurs by the process of electron sharing. 13. There are a number o f different procedures being used in qualitative analysis. 14. The calculation of hydrogen ion concentration in a solution containing a weak electrolytc is a difficult one for the average student first facing this problem. 15. Sulphur dioxide is more than twicc as heavy as air and is one o f the most easily liquefied gases known. 16. The term “heat” of combustion refers to the amount of heat liberated per mole o f the substance burned. 17. Many industrial processes depend for their succcss upon the solubilities of the compounds formed. 18. The system of chemical symbols now used was proposed by the Swedish chemist Berzelius in 1818.19. Fluorine, though for a long time known to exist, was not isolated until 1886. 20. There has been, since earliest times, an atomic hypothesis thought to be implied by the diffusion and the compressibility of gases on the one hand and by the symmetry of crystalline solids on the other. 21. The question o f the composition of air long supposed to be one of the elements was solved only in the 18th century. 22. Dangerous baetcria in drinking water may be killed by small amounts o f chlorine. 23. An clement is represented by certain letters for ease in writing. This symbol stands for one atom of the element. 24. There are numerous methods for demonstrating the spectra of many of the elements. 25. In qualitative analysis there is usually greater difficulty in diagnosing the cations present than in recognizing the anions. 26. In English, We have the practicc of naming chemical elements in Greek and Latin. 27. As a rule, there are several ways o f preparing an element. 28. Mercury has the property, unusual for a metal, of being a liquid at room temperature. 29. The phenomena likely to arise during the experiment must also be taken into account. 30. The amount of the pure metal ccrtain to be obtained for the ore can be calculated in the following way.

Ex. 11. Translate the sentences into English without using a dictionary.

1. Odatda oraliq deb hisoblanadigan suyuq holat ham qattiq moddalar, ham gazlarning ba'zi xususiyatlarini namoyish etadi. 2. Qattiq moddalar suyuqliklardan ham zich. 3. Suyuqlikning zichligi, odatda ishonilganidek, qattiq moddalarning zichligidan atigi 10% kamroqdir. 4. Erituvchi bo'lish qobiliyati har qanday suyuqlikning asosiy xususiyatlaridan biridir. 5. Suyuqlikning molekulyar tuzilishini tasavvur qiling. 6. bu uning xususiyatlarining tabiatini tushunishning eng muhim shartlaridan biri.

Ex. 12. Answer the following questions:

1. What are the main states of matter? 2. What factors determine the properties of liquids? 3. Is there any difference in the density of solids, liquids and gases? 4. Why are liquids usually thought of as solvents? 5. How can one understand the phenomena associated with the liquid state?