Determination of the Solid-Liquid Phase Diagram for Napthalene-Biphenyl Using Thermal Analysis
Experiment #1: Determination of the Solid-Liquid Phase Diagram for Napthalene-Biphenyl Using Thermal Analysis
Objective
To apply thermal analysis to the two-component system, naphthalene-biphenyl at atmospheric temperature. The analysis will be represented by a solid-liquid phase diagram (freezing point diagram).
Theoretical Principles
Phase Equilibria and the Gibbs Phase Rule
This experiment is conducted in order to study a condensed system (solid-liquid) at constant temperature (atmospheric temperature). It should be noted that the atmospheric pressure is unlikely to be the equilibrium pressure for the system. However, equilibria in condensed systems are not very sensitive to pressure.
The freezing point is determined at the specific temperature at which a liquid solution of two component, A and B, begin to separate off to a solid form. Between a range of pure A and pure B, the freezing point will vary (as shown by figure A in the appendix).
The figure contained in the appendix has been developed from the ChE 101 Lab Manual [1]. Based upon this figure the following can be observed.
Freezing point curve spans from B to E and then to A based upon the concentration of A and B within the solution.
The eutectic point is labeled at point E. The eutectic point represents when the solid precipitates of A and B as well as the liquid solution are all present in the mixture. Thus this is the lowest freezing point for the two solids.
Note that A and B in liquid form are miscible.
Solutions of A and B can exist in equilibrium with solid B within the area of BEC.
Solutions of A and B can exist in equilibrium with solid A within the area of AED.
The area above the freezing point curve of BEA represents the liquid mixture of A and B.
The area below CED represents where the 2 solid phases stand with no equilibrium present.
Based on the purpose of keeping the system pressure constant, the Gibbs Phase rule now accommodates this system in the
Objective
To apply thermal analysis to the two-component system, naphthalene-biphenyl at atmospheric temperature. The analysis will be represented by a solid-liquid phase diagram (freezing point diagram).
Theoretical Principles
Phase Equilibria and the Gibbs Phase Rule
This experiment is conducted in order to study a condensed system (solid-liquid) at constant temperature (atmospheric temperature). It should be noted that the atmospheric pressure is unlikely to be the equilibrium pressure for the system. However, equilibria in condensed systems are not very sensitive to pressure.
The freezing point is determined at the specific temperature at which a liquid solution of two component, A and B, begin to separate off to a solid form. Between a range of pure A and pure B, the freezing point will vary (as shown by figure A in the appendix).
The figure contained in the appendix has been developed from the ChE 101 Lab Manual [1]. Based upon this figure the following can be observed.
Freezing point curve spans from B to E and then to A based upon the concentration of A and B within the solution.
The eutectic point is labeled at point E. The eutectic point represents when the solid precipitates of A and B as well as the liquid solution are all present in the mixture. Thus this is the lowest freezing point for the two solids.
Note that A and B in liquid form are miscible.
Solutions of A and B can exist in equilibrium with solid B within the area of BEC.
Solutions of A and B can exist in equilibrium with solid A within the area of AED.
The area above the freezing point curve of BEA represents the liquid mixture of A and B.
The area below CED represents where the 2 solid phases stand with no equilibrium present.
Based on the purpose of keeping the system pressure constant, the Gibbs Phase rule now accommodates this system in the
References: [1] Enns, K., ChE101 Laboratory Manual, p. 17, 19, (University of Waterloo, Waterloo, 2006) [2] J.T