In all
thermodynamic problems energy transfer to or from the system is observed. To
receive, store and deliver energy a working substance is present within the
system. The characteristics which can be used to describe the condition of the
system are known as properties.
Thermodynamic properties are
classified into two categories : intensive and extensive. Intensive properties are independent of
quantity of matter or mass whereas extensive properties are dependent on mass Consider a vessel containing air.
If a membrane is assumed to be introduced into the vessel, such that it
is divided into two equal parts. The
properties remaining unchanged such as pressure and temperature are intensive
properties. Volume of air will be reduced
to half of its initial value. Hence, it is an extensive property.
When a system does not
undergo any change, all the properties have fixed values. This condition is known as a thermodynamic
state.
