Here are some question from first & second laws of thermodynamics and thermodynamic properties.
1. Two
moles of an ideal gas from an initial state of 150°C and 1 bar is compressed isobarically
to 70°C reversibly. Calculate ΔU, ΔH, Q and W for the process. If the process
is carried out irreversibly but so as to accomplish exactly the same changes of
state, calculate ΔU, ΔH, Q and W if it is carried out with an efficiency of
80%. Take CP=(5/2)R
2. Entropy is a state function, should
not depend on the path taken, yet entropy change is different for reversible
and irreversible paths (Clausius inequality). Give the proper justification of
these statements.
3. A heat engine absorbs 250 kJ of
heat from a source at 350 K and rejects heat to two cold reservoirs at 300 K
and 275 K. If the heat rejected to 300 K is 100 kJ, calculate the maximum work
done by the engine.
4. One mole of an ideal gas Cp=7/2R is
compressed adiabatically in a piston-cylinder device from 2 bar and 25°C to 8
bar. The process is irreversible and requires 35% more work than a reversible,
adiabatic compression from the same initial state to the final pressure. What
is the entropy change of the gas?
5.
The equation of state of a certain
substance is given by the expression V= (RT/P - C/T3)and the specific heat is given by the relation Cp=A+BT, where A, B and C are
constants. Derive the expression for the changes in internal energy, enthalpy
and entropy for constant volume process.
6. A gas obeying the
following equation of state P(V − b) = RT is subjected to a Joule-Thomson
expansion. Will the temperature increase, decrease, or remain the same? The Joule-Thomson coefficient is given by (dT/dP)h
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