In the last session, we derived some of

1
In the last session, we derived some of the
thermodynamic relations.
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In this session, we will
derive some more thermodynamic relations and work
out few problems.
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The equation of state of a gas is given by
1
and the specific heat is given by
where a, b and c are constants.
Derive the expressions for changes in internal
energy, enthalpy and entropy for an isobaric
process.
July 2006, VTU
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Isobaric Process
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A perfect gas is heated from 60 to 300oC at a
constant pressure of 4 bar. The gas is then
cooled to 60oC at constant volume. The mass of
the gas is 5 kg. Determine total entropy change.
CP and CV are 1.0 and 0.72 kJ/kg.K
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VTU
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Total entropy change 5(0.152)0.76 kJ / K
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Equation (2) becomes,
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In the next session we will

• Find out what is fugacity
• See how this takes into account non-ideality
• Also determine fugacity of real gases
• Work out numerical problems.