12 Questions
What is the relationship between the excess property change of mixing (DME) and the excess property (ME) according to the text?
DME and ME are the same thing
What is the relationship between the excess volume (VE) and the volume change of mixing (DV)?
VE and DV are the same thing
What is the purpose of studying excess properties according to the text?
To understand the behavior of phase equilibria
What is the definition of the excess property (ME) according to the text?
The difference between the property of a real solution and the property of an ideal solution
What is the relationship between the property change of mixing for a real solution (DM) and the property change of mixing for an ideal solution (DMid) according to the text?
DM is the difference between DMid and the excess property change of mixing (DME)
What is the relationship between the molar property of a solution (M) and the property of an ideal solution (Mid) according to the text?
M is the sum of Mid and the excess property (ME)
What do excess properties represent in thermodynamics?
Deviations from ideal solution behavior
How are excess Gibbs free energy and solution behavior related?
Positive deviation from ideality
What is the significance of excess properties in thermodynamics?
Quantifying deviations from ideal behavior
When is a solution considered to exhibit a positive deviation from ideality?
When excess Gibbs free energy is positive
How are excess functions different from property changes of mixing?
Property changes of mixing relate to activity coefficients
What do partial molar excess functions represent in thermodynamics?
Deviations from ideal solution behavior
Study Notes
Excess Properties in Thermodynamics
- Excess properties in thermodynamic properties like enthalpy, internal energy, heat capacity, etc. do not represent new thermodynamic properties.
- However, excess properties in entropy and entropy-related functions are different from property changes of mixing and represent new and useful quantities.
Definition of Excess Properties
- Excess properties indicate the deviations from ideal solution behavior and are easily related to activity coefficients.
- Excess properties can be positive or negative, depending on the deviation from ideality.
Partial Molar Excess Functions
- The definition of partial molar excess functions is analogous to that of partial molar thermodynamic properties.
- The partial molar excess property of component i is denoted by M.
- The partial molar excess function can be written as A M-EM.
Excess Property Change of Mixing
- The excess property change of mixing is defined as the difference between an actual property change of mixing and the property change of mixing calculated for an ideal solution.
- The excess property change of mixing is denoted by DME.
- DME is equal to the excess property ME.
Example of Excess Volume
- The excess volume of a solution is denoted by VE.
- VE is equal to the volume change of mixing DV, since ideal solution involves no volume change of mixing.
- The excess volume of a solution and the volume change of mixing are the same.
Explore the concept of excess properties in chemical thermodynamics and their significance in the treatment of phase equilibria. Understand the difference between the property of a real solution and that of an ideal solution.
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