3 Part One. The Predicate

Section II
Mashq 1. Quyidagi xalqaro so’zlarni ma’nosini toping:

convert, hypothetical, contract, absorption, mole, entropy, compromise, deduce, argument, energetically, chaos, generalization, rationalize, accompany, anticipate

Mashq 2. Quyidagi so/zlar yodingizda bo’lsa ayting: melt, in turn, stage, involve, represent, extend, evolution, infinitely, likewise, markedly, subtle
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Matnni o’qing (o’qish vaqti —3,5 daqiqaы).

Nonideal Solutions
Consider a solid substance dissolving in a liquid solvent. The solid is such that when melted, it is converted to a liquid that, in turn, can form an ideal solution with the solvent. The dissolution of the solid can be pictured as occurring in two hypothetical stages:

solid solute → liquid solute → solute in solution.

The second of these steps does not involve any energy change, for the solution formed is ideal. In contrast, the first step does involve the absorption of energy in the amount per mole of solute. Consequently,while the tendency toward maximum entropy favours the dissolution of the solid, the tendency toward minimum energy favours the solid remaining undissolvcd. Therefore, the solubility of the solid is limited, and a saturated solution which represents the best compromise between maximizing entropy and minimizing energy is formed. Since ΔН_fus, is related to the strength of attractive forces between solute molecules, We can deduce that the magnitudes o f these same forces determine the solubility of the solid in ideal solutions.

By using some care, we can extend our aigumcnts to nonidcal solutions. Two liquids which mix with the evolution o f heat will be infinitely soluble in each other, for both energy and entropy ciTccts favour their mixing. Two liquids which mix with the absorption o f heat may have limited solubility in each other, for if the mixing process is energetically unfavourable, the tcndcncy toward maximum molecular chaos may or may not be sufficient to allow the liquids to mix in all proportions. Likewise, the solubility o f a solid is likely to be small if it enters the solution only with considerable absorption of heat. On the other hand, if the dissolution of the solid is accompanied by evolution o f heat, the solubility of the solid may be quite high. Even with these generalizations it is difficult to predict or even rationalize qualitatively the solubilities of substances that form markedly nonidcal solutions, for the energy and entropy changes that accompany the mixing of strongly irrcacting molecules are subtle and difficult to anticipate.

Mashq 3. Matnning asosiy tarkibini bir nechta jumlalarda ko'rsating.

Mashq 4. Matndagi qaysi so'z "tasavvur qiladi"?

Mashq 5. Matnda quyidagi savollarga javob toping:

1. What hypothetical steps can be pictured when a melted solid is dissolved? 2. At what stage does the energy change take place? 3. Why is the solubility of the solid limited? 4. What two liquids will be infinitely soluble in each other? 5. When will the solubility of the solid be high?

Mashq 6. Quyidagi jumlalarni to'ldiring:

1. The magnitudes of the attractive forces determine... 2. Two liquids will be infinitely soluble in cach other if they mix with... 3. Two liquids mixing with the absorption of heat may have... 4. It is difficult to predict...5. If the dissolution of the solid is accompanied by evolution of heat...