Chapter "1"
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.
"Some Important common Thermodynamics terms"
1- System: the part of the universe selected for thermodynamic
study as boiling of water in beaker.
2- Surroundings: the remaining part of the universe around the
system which is not under study. For example, boiling of water
in a beaker is an example of system and everything else around
the beaker is the surroundings.
3- Boundary: the region separating the system from
surroundings: for example the wall of the beaker act as
boundary wall because it separates the system and surroundings.
Types of System:
The system may be classified into three categories:
1- open system: A system which can exchange matter as well as
energy with its surroundings such as boiling of water in an open
beaker.
2- Closed system: a system which may exchange energy but not
matter with surroundings such as steam inside the vessel.
3- Isolated system: A system which can neither exchange matter
nor energy with the surroundings.
Homogeneous System: A system is said to be homogeneous if it
is uniform throughout. Such type of system consists of only one
phase. For example a system containing only a pure solid or a
pure liquid or a pure gas or completely miscible liquids or gases.
Heterogeneous System: if the system is not uniform throughout.
Such type of system consists more than one phase, for example
a system containing a mixture of two immiscible liquids or
gases or solids.
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.