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1. Science
Shree Shitaladevi Community Secondary School
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Grade - 9
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2. UNIT: Solubility
• A mixture is defined as a mass obtained by mixing up two or more chemically
non-reactive substances in any proportion by weight. There are two types of
mixture. They are as follows:
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3. Types of Mixture
1. Homogeneous mixture:
A homogeneous mixture is defined as a mass in which the
particles of the components of the mixture are equally distributed.
Examples: Sugar solution, air, alcohol water, brass, soda water
etc.
2. Heterogeneous mixture
• A heterogeneous mixture is defined as a mass in which the
particles of components of the mixture are not equally
distributed. Examples: Smoke, Oily water, Sandy water, etc.
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4. Solubility
• Solution = solute + solvent
Solute: It is the component of a solution, which gets dissolved into
other substance to form a solution.
Solvent: It is the substance, which dissolves solute to form a solution.
Water: It is a universal solvent that has the capacity of dissolving
many substances like common salts, copper sulphate, sugar, etc.
Alcohol: It found in the form of spirit and can dissolve resin and
iodine.
Petrol and kerosene: It dissolves ghee, grease, oil, fat, etc. and is
used for removing clothes stain.
Ether: It is an organic solvent that can dissolve fat, oil, resin, etc.
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5. • Saturated solution
The solution in which the solvent cannot dissolve the solute anymore, at
the given temperature then it is known as saturated solution at that
temperature.
When we dissolve solute in a solvent and there comes a time when the
solute won't get dissolved anymore, then this solution is considered as
saturated solution.
• Example: When we pour sugar in the water and stir it, the sugar keeps
dissolving but on further dissolving the sugar, a state will come when
the sugar will not get dissolved in the water. At this point, the solution
is a saturated solution.
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6. • Unsaturated solution
The solution which can dissolve the solute at the given temperature
is known as unsaturated solution at that temperature.
• Solutions having low concentration of solute particles are
called dilute solution.
• Solutions having high concentration of solute particles are
called concentrated solution.
Supersaturated Solution:
The saturated solution at a higher temperature that holds excess
solute than the required amount for a saturated solution at that
temperature is called supersaturated solution.
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7. Solubility
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• Solubility of the substance
The amount of solute required to form a solution in 100 gm of solvent at a
particular temperature to give saturated solution is the solubility of that
solute at that temperature.
• The solubility of a substance at certain temperature can be given by
Weight of solute (gm)
Solubility = x 100
Weight of solvent (gm)

8. Solubility
• Effect of the temperature on solubility
The relationship between increase in temperature and solubility is that
the solubility is directly proportional to the increase in the temperature.
i.e. At high temperature the solubility of a solution is high so it is able
to dissolve more solute, but when it is cooled, the solubility of the
solution decreases and due to which the solute separate out as solid.
• Solubility curve
Solubility curve is curve obtained by the plotting the solubility of the
substance at different temperature against these temperatures.
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9. Solubility Curve
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10. Solubility Curve
From the solubility curve various information can be obtained which are
listed below:
I. Comparative study of the solubility of different solutes can be done.
II .The solubility of solute at any temperature can be found out.
III. The change in solubility on changes in temperature can be observed.
• Crystal
A solid which has certain geometrical shape and certain boiling and
freezing point is called crystal. It is formed by the process of
crystallization.
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11. Crystal
Characteristics of Crystals:
i) They are the solid particles with a definite shape.
ii) They are pure substances.
iii) They have fixed melting point.
iv) They are arranged in three dimensional patterns.
Crystallization:
The process in which crystals are formed by cooling a hot saturated
solution of the solid substance which can give crystals is called
crystallization.
In other words, the process of formation of crystals is called crystallization.9/13/2020www.yepnepal.com
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12. Crystalline Solid:
A solid which has certain shape and certain boiling and freezing point is
called crystals. The substances that can form crystals are called
crystalline substances.
For Example: NaCl, CuSO4 etc.
Amorphous Solid:
A solid which has no fixed geometrical shape is known as amorphous.
These substances can not form crystals.
For Example: Glass, rubber, plastic etc.
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13. Any Questions?
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14. Exercise
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15. Exercise
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16. Exercise
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17. Numerical Problems
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18. Numerical Problems
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