thermodynamics ,chemical kinetics and catalysis

Engineering
Chemistry
Module -1


A.
Thermodynamic
s

,Thermodynamics: Basic Terminologies

the quantity of matter or a region Properties of a sy
Thermodynamic Systems: in space upon which attention is # Intensive Proper
concentrated in the analysis of a
problem
Everything
external to
the system




# Extensive Prop

,Thermodynamics: Basic Terminologies

Internal energy (U)
# State function: = Kinetic energy + Potential energy
Depends on the initial state & final state;
independent of the path used to reach from.  It’s a state function & an extensive pr
Example: T (Temperature), P (Pressure), U (Internal the system.
energy), H (Enthalpy) etc.  Internal energy of a system changes wh
is transferred into or outside the syste
form heat or work




# Path function:
𝜟𝑼𝒔𝒚𝒔𝒕𝒆𝒎=𝑼𝒇𝒊𝒏𝒂𝒍 𝒔𝒕𝒂𝒕𝒆−𝑼𝒊𝒏𝒊𝒕
Depends on the path between the initial & final state
Example: W (work done), q (heat transferred) etc.

, Thermodynamics: Basic Terminologies
State of a system
 The state of thermodynamic variables such as Work done on/by the system
pressure, temperature, volume, composition W (Work) = F (force) x w (distance moved in the direc
which describes the system is called state of
the system.
 when one/more variables undergo change,
the system is said to have undergone a
change of state
• Adiabatic – no heat transferred
• Isothermal – constant temperature
• Isobaric – constant pressure
• Isochoric – constant volume

 Gas is heated  it will expand and push the piston, thereby doing work on the piston.

The work done (dw) when the system expands by dV against a pressure Pex: dw = −Pe
Total work done by the system to expand from volume Vi to Vf: W = -

 This is an example of the system doing the work on the surrounding