Factors Affecting Solubility – Introduction to fundamental concepts of Biological Science including the organization and common characteristics of living matters, cell structures and functions, food production by photosynthesis, harvesting energy, mechanism of cells reproduction, genetics, evolutions, and Human Biology. Introduction to general chemistry including basic concepts about matter, atomic structure, chemical bonds, gases, liquid, and solids, solutions, chemical reactions, acid, bases, and salt;
organic and biochemistry including hydrocarbons and their derivatives, carbohydrates, lipids, proteins, enzymes, vitamins, and minerals, nucleic acids; principles of physics and applications to nursing including gravity and mechanics, pressure, heat and electricity; nuclear chemistry and nuclear physics, effects of radiation on human beings, and protection and disposal. The aim of the course is to acquire knowledge and skills in general biological science, general chemistry and physics.
Factors Affecting Solubility
Since this topic is mainly concerned with solutions that have solid solutes, the factors that influence their solubility are as follows:
1. Nature of the solute and solvent: The proper selection of a solvent is necessary for dissolving a solid substance (solute). Water is a common solvent for many solutes, such as sugar and salts, but it is suitable for fats and paints. Iodine is slightly soluble in water but readily dissolved in alcohol. Ether, CCl4, and gasoline are good solvents for fats, whereas turpentine is used to dissolve paint.
2. Surface: A finely powdered solute will dissolve more rapidly because more surfaces is exposed to the solvent.
3. Agitation: If the mixture is stirred, the rate of solubility of the solute is increased, since fresh solvent is continually coming into contact with the solute.
4. Temperature: The solubility of most solutes increases with a rise in temperature. Whereas the solubility of gases is decreased by a rise in temperature and is increased by an increase in pressure, e.g., when a cold bottle of soda water is opened, the pressure is released and the gas, CO2 escapes slowly from the solution, forming bubbles in the water.
Types of Solutions:
1. Dilute and concentrated solutions:-When a solution contains a small percentage of the solute that could be dissolved in the solvent, it is said to be diluted; when it contains a large percentage of solute, then the solution is said to be concentrated.
2. Saturated solution:-If a solution is prepared by stirring an excess of solute until no more will dissolve, it is said to be a saturated solution.
3. Supersaturated solution:-When a saturated solution is prepared at higher temperature and is then allowed to cool, the extra solute that was dissolved at the higher temperature usually becomes insoluble and settles out of the solution. If the hot solution is cooled slowly and is not disturbed, the excess solid may not settle out. In this case the solution will contain more solute than it can ordinarily dissolve at room temperature. Such a solution is called a supersaturated solution. Freshly prepared jams and jellies are common examples of supersaturated solutions.
Physiological Saline Solution:
This is a solution in which the solute is in the proportion of the salt concentration in the blood. It is 0.9% NaCl solution.
Uses:
A physiological saline solution is used under following conditions:-
- When the body has lost much fluid.
- Post-operative shock.
- In dehydration due to severe diarrhea.
- In streptococcal infection.
If one has a lower osmotic pressure than the other, the first is said to be hypotonic with respect to the second. A hypotonic solution has a lower osmolarity than the one to which it is compared. A hypertonic solution is one with a higher osmotic pressure than other.
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