introduction

Chapter "1"
Understanding of phase diagrams is fundamental and essential to the study of materials science, and an understanding of thermodynamics is fundamental to an understanding of phase diagrams.
The term “thermodynamics” is introduced by Lord Kelvin in 1849 by combining two Greek words thermo (heat) and dynamics (force or motion)
Thermodynamics: is an impressive branch of physical science which deals with the relationships between all forms of energy such as heat, chemical energy, mechanical or electrical work and the macroscopic properties of material system because thermodynamics deals with the general laws govering the transformations of macroscopic system without taking into account the microscopic mechanisms.

Chemical Thermodynamics:
Chemical Thermodynamics studies energy relationships between Enthalpy, Entropy, Equilibrium, and Gibbs free energy. Thermodynamics can predict the spontaneous direction of a reaction under specified conditions, but not the rate of the reaction.
Thermodynamics vs. Kinetics:
Which one deals with state functions, independent of path?







Macroscopic System: A macroscopic system is that which consist of a large number of species (atoms, ions, or molecules) and the properties associated with the macroscopic system are called macroscopic properties. For example: temperature, pressure, composition, density, mass, refracting index, viscosity, surface tension, enthalpy internal energy. Macroscopic properties subdivided into two categories:
1- Extensive properties: the properties which depend on the amount of the material in the system. Such as volume heat capacity, internal energy, free energy, entropy.
2- Intensive properties: the properties which do not depend (independent) on the amount of the material but depend upon the nature of the material in the system are called intensive properties. For example, viscosity, surface tension, thermal conductivity, boiling point, freezing points, refractive index, vapour pressure of a liquid, temperature, density, specific heat, etc.
Thermodynamic Equilibrium
A system is said to be in a state of thermodynamic equilibrium if macroscopic properties of the system do not change with time. It implies the simultaneous existence of the following three types of equilibria in the system:-
i) thermal equilibrium. A system is said to be in thermal equilibrium if there is no flow of heat from one portion of the macroscopic system to another portion. This is possible only if the temperature remains the same throughout in all parts of the system.
ii) Mechanical equilibrium. A system is said to be in mechanical equilibrium of no mechanical work is done by one part of the macroscopic system to another part of the system. This is possible only if the pressure remains constant throughout in all parts of the system.
iii) Chemical equilibrium. A system is said to be in chemical equilibrium if the composition of the various phases in the system does not change with time.
Thermodynamic Properties
A system is always defined by measurable properties like pressure, volume, temperature and the amount of substance etc. these properties are called thermodynamic properties. Work (w) and heat (q) are not the stable variables but due to their frequent occurrence they are also regarded as thermodynamic properties.

The Nature of Energy
Definition of Energy: The capacity to do work or to produce heat
Energy classification: Potential energy Kinetic energy

Potential Energy: Energy due to position or composition as
• Water behind a dam has potential energy
• The energy released when gasoline is burned results from differences in the attractive forces between nuclei and electrons in the reactants and products.
Kinetic energy: Due to the motion of the object and depends on the mass of the object (m) and its velocity.
Energy Transfer through…
-Work Defined as a force acting over a distance
- Heat :
1.Involves the transfer of energy between two objects due to a temperature difference.
2.NOT a substance contained in an object.
– Heat and temperature are decidedly different.
– Temperature is a property that reflects the random motion of the particles in a particular substance. The temperature of a monatomic ideal gas is an index of the average random translational energy of the gas.
-The science of measuring heat based on observing the temperature change when a body absorbs or discharges energy as heat.
***********A State Function (Property)