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| Chemistry |
How much of copper sulphate crystals will be seperated if 25g saturated solution of copper sulphate at 60oC is cooled down to 30oC if solubility of copper sulphate at 60oC is 50 and at 30oC is 30 respectively?
According to the statement:
At 60oC, 50 g of CuS04 forms 150 g of
saturated solution (50g solute+ 100g solvent)
At 30oC, 30 g of CuS04 forms 130 g of
saturated solution (30g solute+ 100g solvent)
The difference in the weight of solution is: 150 - 130 = 20g
Therefore, 150g of saturated solution when cooled from 60oC
to 30oC separates 20g of CuS04
1g of saturated solution when cooled from 60oC to
30oC separates 20/150 g of CuS04
25g of saturated solution when cooled from 60oC
to 30oC separates of (20/150)*25g CuS04 = 3.33g
Thus 3.33 g copper sulphate is separated by cooling the
solution from 60oC to 30oC.
Heterogeneous mixture:
A mixture which can be seen through our naked eyes is called heterogeneous mixture. E.g. mixture of sand and rice or which can be separated by easily.
According to
the particle size mixture can be divided into three types
Solution:
Homogeneous mixture of two or more
substances is called solution. Example: Salt and water, alcohol and water, Air,
brass etc. The substance which is dissolved is called solute and the substance
that dissolves is called solvent. In the solution the diameter of the particle
of a substance is smaller than 10-5 cm. They are Invisible (Visible
under ultra-microscope). They cannot be settle down and can't be filtered. They
are transparent and Homogeneous.
Solution =
solvent + solute
Colloids:
If the diameter of the particle of a
substance in a solution ranges from 10-5 cm
to 10-7 cm then the mixture is
called colloidal. Particle size in colloidal solution is intermediate between
solution and suspension. The particles of colloids cannot be seen by naked eye.
They may be visible in beam of light, Do not settle down in ordinary condition,
cannot be filtered, cloudy transulent and Intermediate of homogeneous and
Heterogeneous.
Example: RNA,
DNA in blood, particles of milk, Gum, Dust in air
Suspension:
It is the heterogeneous mixture of
solid and liquid particles in which particle size is 10-3 cm
or bigger. They are visible in naked eye, settle down easily, can be filtered,
apaque, They are Heterogeneous.
E.g. smoke particles in air, Sand water, Muddy
water etc.
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.
OR
The solution which cannot dissolve
excess amount of solute in it at the given temperature is call unsaturated
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. On Heating it becomes
unsaturated. It has more density. it has more concentration of solute, precipitation
of the of the solute appears on cooling.
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.
Unsaturated solution
A solution at
a state before saturation in called an unsaturated solution. In other words,
the solution which can dissolve the solute at the given temperature is known as
unsaturated solution at that temperature.
The solution which can dissolve excess amount of solute in it
at the given temperature is call unsaturated solution at that temperature.
On Heating it remains unsaturated. It has less density. it has less concentration of solute, precipitation of the of the solute doesn't appears on cooling.
Solutions having low concentration of
solute are called dilute solution.
Solutions
having high concentration of solute are called concentrated
solution.
Supersaturated solution:
The saturated
solution at higher temperature that holds excessively more solute then the
required amount for saturated solution at that temperature is called
supersaturated solution.
When excess amount
of solute particle is dissolve in a solution when heating is known as
supersaturated solution.
Importance of Solution
- Oxygen is found
dissolved in water and in air which is used by living organism for respiration.
- Plants take
different minerals and salts from the soil in the form of a solution.
- The digested food
particles reach the different parts of the body in the form of a solution.
- Most of the
reaction taking place easily in the form of solution.
- Solution is more
essential in many industries.
Solubility of the substance
The solubility
of a substance (Solute) at a given temperature is defined as the amount of the
substance(Solute) dissolved in 100g of solvent to make a saturated solution at
that temperature.
The solubility
of a substance at certain temperature can be given by
Solubility S
= ( weight of solute in g/weight of solvent in g) * 100 [At constant
Temperature]
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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| 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
crystal is a piece of solid particles which has a regular geometrical shape,
smooth surfaces and sharp edges. They are solid particles with a definite or
regular shape. They are pure substance with a fixed melting point.
Crystallization:
When the
saturated mixture of a solid in a liquid at a high temperature is allowed to
cool down, solid deposits in a certain geometrical shape called crystal .The
process in which crystals are formed by cooling a hot saturated solution of
solid materials is known as crystallization.
Amorphous solid:
Those solid substance which do not
have any definite geometrical shapes are called Amorphous solid. On heating
they don't melt but becomes less viscous. Lime, glass, rubber, plastic etc.
Crystalline Solids:
Crystalline Solids have typical
geometrical shaped along with definite and rigid morphology. Eg; NaCl, Copper
sulphate etc. are crystalline solid.
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