Title :
Determination of Phase Diagram for Ethanol/ Toluene/ Water System Theory(Three Component System)
Date
3 November 2014
Objectives
1.Determination of the solubility limits in a ternary system of water and two other liquids (ethanol and toluene), one of which is completely miscible (ethanol) and the other is partly miscible with water (toluene)
2.Construction of the solubility curve of the system being studied on triangular diagram.
Introduction
The making of pharmaceutical formulation often involve the mixing of multiple component together to achieve homogenous form.This is usually possible by knowing exact ratio of each component that needs to be mixed with taking consideration of temperature.This practical use three component of concern which were Ethanol,Water and Toluene.Water and Toluene are practically insoluble,as the mixing of the three component progress,the three component can reach homogenous state at equilibrium if such right component proportion were used.
To present a three component system,ternary diagram is needed. Each side of a triangular diagram correspond one of the three component in the system and can be divided into part to produce equilateral grids as shown above. Thus any point in the diagram will show the amount of all three components while a point on the sides will show amount of any two components with each apex represent an amount of 100% of any one of the three components.
Following the basis of describing the effect of intensive variable to various phase in a system at equilibrium, which is the phase rule, it is determine that this system have 4 degrees of freedom. The four degrees of freedom are - temperature, pressure, and any two from the three component concentration.
F = C – P + 2
F = 3 – 1 + 2
F = 4
Apparatus and Materials
1.Eight 100cm3 conical flask
2.Burette
3.Toluene
4.Ethanol
5.Distilled water
Procedure
1.Eight, 20 ml solution of toluene and ethanol were prepared in eight different 100cm3 conical flasks. Each flash were filled so that it contain 10%, 25%, 35%, 50%, 65%, 75%, 90% and 95% of ethanol with the rest was toluene.
2.The conical flask were labelled A, B, C, D, E, F, G and H respectively. Measuring these component were done by using a burette to make sure accuracy.
3.Each flask were titrated with burette filled with water and stopped when the solution in the flask turn cloudiness.The amount of water used in the titration was calculated and ratio of each component was calculated and tabulated in the figure below.
Result
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Questions
Does
the mixture containing 70% ethanol, 20% water and 10% toluene (volume) appear
clear or does it form two layer?
The
mixture will appear as clear solution.
What
will happen if you dilute 1 part of the mixture with 4 parts of
(a) Water
Two phases will be
observed.
(b) Toluene
Two phases will be observed.
(c) Ethanol
One phase will be
observed.
Discussion
Each apex on the triangle representing
the ternary system represents 100% of the component at that apex. The side of
the triangle, directly opposite the apex, represents 0% of the apex component.
Compositions of points which lie along the outside edge of the triangle are
simply a mixture of the two components at each end of the tie line, with 0% of
the third component. In this experiment, A represents ethanol, B
represents toluene while C represents water. The three lines joining the corner
points represent two-component mixtures of the three possible combinations of
A, B and C. Thus the lines AB, BC and CA are used for two-component mixtures of
A and B, B and C, and C and A, respectively.
In this experiment, the system
contains 3 components which are ethanol, toluene and water but only one phase.
Thus, according to Gibbs’ phase rule F = 3-1+2 =4. 4 degrees of freedom
included temperature, pressure, and the concentrations of two of the three
components are required. Only concentrations of two components are required
because concentration of the third component can be obtained by further
calculation.
This experiment was conducted under constant temperature and
pressure.
From the data of the
experiment, the plotted graph inside the triangular diagram formed a binomial
curve. The region bounded by the curve shows the present of two liquid phases
so the mixture is cloudy. The cloudy solutions formed indicates the phase
separation, this is due to the insufficient amount of ethanol to produce a
homogenous mixture. When the amount of ethanol is high, it will acts as
surfactant which allow the two liquid phases become single liquid phase.
Meanwhile, the single liquid phase of homogenous solution was shown at the
region above the curve. We can conclude that ethanol helps to increase the
miscibility of the two other components.
There are several errors we had done during the experiment. Firstly, we poured
and left the ethanol and toluene in the conical flask for a long time. Since
ethanol and toluene are volatile liquids, their volume may be less than the
actual one as some of them already evaporates. Therefore, the result was
affected. Besides, parallax error may occur due to our eyes level was not
perpendicular to the reading scale while measuring the volume of water in the
burette. Furthermore, the room temperature in the laboratory may not constant
thus affected the result obtained at the end of the experiment. Moreover, a random
error occurred due to different person doing the observation. This is because
different degree of cloudiness was achieved and the volume of water added
obtained was inaccurate.
To get an accurate result, there are some precaution steps that need to be
taken. Firstly, the mixture of toluene and ethanol should be titrated
immediately to prevent vapourisation or it should be sealed since both toluene
and ethanol are volatile liquid. We must ensure that the eye is placed
perpendicularly to the meniscus of the liquids to avoid parallax error. In
addition, the temperature of the surrounding must be fixed and constant when
carry out the experiment. One more important precaution step is only one
observer is allowed to do the titration to make sure that the degree of
cloudiness is same. Therefore, a more accurate result can be obtained.
Conclusion
Phase diagrams are graphical
representations of the liquid, vapour, and solid phases that co-exist at various
ranges of temperature and pressure within a reservoir. Ternary phase diagrams
represent the phase behaviour of mixtures containing three components in a
triangular diagram. This experiment of ternary system involve three different
liquids which are ethanol, toluene, and water and is represented using a
triangle. From the experiment, as the number of volume of ethanol by percentage
increase and number of volume of toluene by percentage decrease, the volume of
water will increase. The two phase system was established once the cloudiness
was observed. Water and toluene form a two-phase system due to they are
only slightly miscible. However, ethanol is completely miscible with both
toluene and water.
Reference
1.http://petrowiki.org/Ternary_phase_diagrams
2.http://www.brocku.ca/earthsciences/people/gfinn/petrology/ternary3.htm
3.http://gibbs.uio.no/phase_rule.html
Title :
Determination of Phase Diagram for Ethanol/ Toluene/ Water System Theory(Three Component System)
Date
3 November 2014
Objectives
1.Determination of the solubility limits in a ternary system of water and two other liquids (ethanol and toluene), one of which is completely miscible (ethanol) and the other is partly miscible with water (toluene)
2.Construction of the solubility curve of the system being studied on triangular diagram.
Introduction
The making of pharmaceutical formulation often involve the mixing of multiple component together to achieve homogenous form.This is usually possible by knowing exact ratio of each component that needs to be mixed with taking consideration of temperature.This practical use three component of concern which were Ethanol,Water and Toluene.Water and Toluene are practically insoluble,as the mixing of the three component progress,the three component can reach homogenous state at equilibrium if such right component proportion were used.
To present a three component system,ternary diagram is needed. Each side of a triangular diagram correspond one of the three component in the system and can be divided into part to produce equilateral grids as shown above. Thus any point in the diagram will show the amount of all three components while a point on the sides will show amount of any two components with each apex represent an amount of 100% of any one of the three components.
Following the basis of describing the effect of intensive variable to various phase in a system at equilibrium, which is the phase rule, it is determine that this system have 4 degrees of freedom. The four degrees of freedom are - temperature, pressure, and any two from the three component concentration.
F = C – P + 2
F = 3 – 1 + 2
F = 4
Apparatus and Materials
1.Eight 100cm3 conical flask
2.Burette
3.Toluene
4.Ethanol
5.Distilled water
Procedure
1.Eight, 20 ml solution of toluene and ethanol were prepared in eight different 100cm3 conical flasks. Each flash were filled so that it contain 10%, 25%, 35%, 50%, 65%, 75%, 90% and 95% of ethanol with the rest was toluene.
2.The conical flask were labelled A, B, C, D, E, F, G and H respectively. Measuring these component were done by using a burette to make sure accuracy.
3.Each flask were titrated with burette filled with water and stopped when the solution in the flask turn cloudiness.The amount of water used in the titration was calculated and ratio of each component was calculated and tabulated in the figure below.
Result
Questions
Does
the mixture containing 70% ethanol, 20% water and 10% toluene (volume) appear
clear or does it form two layer?
The
mixture will appear as clear solution.
What
will happen if you dilute 1 part of the mixture with 4 parts of
(a) Water
Two phases will be
observed.
(b) Toluene
Two phases will be observed.
(c) Ethanol
One phase will be
observed.
Discussion
Each apex on the triangle representing
the ternary system represents 100% of the component at that apex. The side of
the triangle, directly opposite the apex, represents 0% of the apex component.
Compositions of points which lie along the outside edge of the triangle are
simply a mixture of the two components at each end of the tie line, with 0% of
the third component. In this experiment, A represents ethanol, B
represents toluene while C represents water. The three lines joining the corner
points represent two-component mixtures of the three possible combinations of
A, B and C. Thus the lines AB, BC and CA are used for two-component mixtures of
A and B, B and C, and C and A, respectively.
In this experiment, the system
contains 3 components which are ethanol, toluene and water but only one phase.
Thus, according to Gibbs’ phase rule F = 3-1+2 =4. 4 degrees of freedom
included temperature, pressure, and the concentrations of two of the three
components are required. Only concentrations of two components are required
because concentration of the third component can be obtained by further
calculation.
This experiment was conducted under constant temperature and
pressure.
From the data of the
experiment, the plotted graph inside the triangular diagram formed a binomial
curve. The region bounded by the curve shows the present of two liquid phases
so the mixture is cloudy. The cloudy solutions formed indicates the phase
separation, this is due to the insufficient amount of ethanol to produce a
homogenous mixture. When the amount of ethanol is high, it will acts as
surfactant which allow the two liquid phases become single liquid phase.
Meanwhile, the single liquid phase of homogenous solution was shown at the
region above the curve. We can conclude that ethanol helps to increase the
miscibility of the two other components.
There are several errors we had done during the experiment. Firstly, we poured
and left the ethanol and toluene in the conical flask for a long time. Since
ethanol and toluene are volatile liquids, their volume may be less than the
actual one as some of them already evaporates. Therefore, the result was
affected. Besides, parallax error may occur due to our eyes level was not
perpendicular to the reading scale while measuring the volume of water in the
burette. Furthermore, the room temperature in the laboratory may not constant
thus affected the result obtained at the end of the experiment. Moreover, a random
error occurred due to different person doing the observation. This is because
different degree of cloudiness was achieved and the volume of water added
obtained was inaccurate.
To get an accurate result, there are some precaution steps that need to be
taken. Firstly, the mixture of toluene and ethanol should be titrated
immediately to prevent vapourisation or it should be sealed since both toluene
and ethanol are volatile liquid. We must ensure that the eye is placed
perpendicularly to the meniscus of the liquids to avoid parallax error. In
addition, the temperature of the surrounding must be fixed and constant when
carry out the experiment. One more important precaution step is only one
observer is allowed to do the titration to make sure that the degree of
cloudiness is same. Therefore, a more accurate result can be obtained.
Conclusion
Phase diagrams are graphical
representations of the liquid, vapour, and solid phases that co-exist at various
ranges of temperature and pressure within a reservoir. Ternary phase diagrams
represent the phase behaviour of mixtures containing three components in a
triangular diagram. This experiment of ternary system involve three different
liquids which are ethanol, toluene, and water and is represented using a
triangle. From the experiment, as the number of volume of ethanol by percentage
increase and number of volume of toluene by percentage decrease, the volume of
water will increase. The two phase system was established once the cloudiness
was observed. Water and toluene form a two-phase system due to they are
only slightly miscible. However, ethanol is completely miscible with both
toluene and water.
Reference
1.http://petrowiki.org/Ternary_phase_diagrams
2.http://www.brocku.ca/earthsciences/people/gfinn/petrology/ternary3.htm
3.http://gibbs.uio.no/phase_rule.html
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