Scribd
Upload
66 views2 pages

Entropy

The document presents a series of problems related to entropy changes in various thermodynamic scenarios involving copper blocks and air, including calculations for heat transfer and mixing processes. It also includes theoretical questions discussing the significance of entropy, the second law of thermodynamics, and the irreversibility of processes. The problems and theories aim to deepen understanding of entropy and its implications in thermodynamics.

Uploaded by

anmolsrivastava296
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
66 views2 pages

Entropy

The document presents a series of problems related to entropy changes in various thermodynamic scenarios involving copper blocks and air, including calculations for heat transfer and mixing processes. It also includes theoretical questions discussing the significance of entropy, the second law of thermodynamics, and the irreversibility of processes. The problems and theories aim to deepen understanding of entropy and its implications in thermodynamics.

Uploaded by

anmolsrivastava296
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 2

Entropy

Problems:
1. A copper block of 600g mass and with Cp of 150 J/k at 1000C is
placed in a lake at 80C. Calculate the entropy change of the
universe.
2. Determine entropy change of universe, if two copper blocks of 1 kg
& 0.5 kg at 150ºC and 0ºC are joined together. Specific heats
for copper at 150ºC and 0ºC are 0.393 kJ/kg K and 0.381 kJ/kg K
respectively?
3. Determine the change in entropy of universe if a copper block of 1
kg at 150ºC is placed in a sea water at 25ºC. Take heat capacity of
copper as 0.393 kJ/kg K.
4. Two insulated tanks containing 1 kg air at 200 kPa, 50°C and 0.5 kg
air at 100 kPa, 80°C are connected through pipe with valve. Valve is
opened to allow mixing till the equilibrium. Calculate the amount of
entropy produced.
5. Determine the net change in entropy and net flow of heat from or to
the air which is initially at 105 kPa, 15°C. This 0.02 m3 air is heated
isochorically till pressure becomes 420 kPa and then cooled
isobarically back up to original temperature.
6. Air initially at 103 kPa, 15°C is heated through reversible isobaric
process till it attains temperature of 300°C and is subsequently
cooled following reversible isochoric process up to 15°C
temperature. Determine the net heat interaction and net entropy
change.
7. Air at 20°C and 1.05 bar occupies 0.025 m3. The air is heated at
constant volume until the pressure is 4.5 bar, and then cooled at
constant pressure back to original temperature. Calculate : (i) The
net heat flow from the air. (ii) The net entropy change. Sketch the
process on T-s diagram.

Theory questions:

1. Discuss the significance of Clausius inequality.


2. Define the ‘entropy’. Also explain how it is a measure of irreversibility?

3. Explain the difference between isentropic process and adiabatic


process.

4. How does the second law of thermodynamics overcome limitations of


first law of thermodynamics?

5. Show that entropy of universe is increasing.

6. Is the adiabatic mixing of fluids irreversible? If yes, explain.

7. Why does entropy generally increase? Explain.

8. Explain the entropy principle and apply it to a closed system.

9. How the feasibility of any process can be ensured?

10.List principles of increase of entropy and derive the expression for


change in entropy of universe by mixing of two fluids?

11.Explain Clausius inequality and derive the conditions?

12.Explain Clausius theorem with neat sketch?

You might also like