Solve Difficult ThermalDynamics Questions

  • Thread starter Lil Frank
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In summary, the conversation discusses various thermodynamic and statistical concepts, including entropy, heat transfer, and ideal gas processes. The first question asks for an explanation of why heat always flows from high temperature to low temperature objects in the absence of external work, using the concept of entropy. The second question involves constructing plots for different thermodynamic processes and identifying the initial and final states. The third question asks for a derivation of the bulk modulus and speed of sound in an ideal gas, using statistical mechanics. Finally, the fourth question is the most difficult one and asks for a derivation of the change in entropy for a reversible process in an ideal gas, as well as using statistical mechanics to calculate the change in entropy for a free expansion process. The person asking
  • #1
Lil Frank
2
0
Following questions are from my final. I found them pretty difficult. I hope someone help me with them. Thank you.

1 Please give a clear argument by using the concept of entropy to explain that the heat will always flow from the high temperature to the low temperature objects if there is no external work.

2 Please construct the plots of P versus V, T versus S, and S versus E_internal (a) for the isothermal expansion and isobaric expansion thermodynamic process.
(b) for the adiabatic expansion thermodynamic process.(Please point out the initial and final state on your curve.)

3 For adiabatic processes in an ideal gas, show that
(a)the bulk modulus is given by
dp
B = -V ——— =γP
dV And therefore
(b)the speed of the sound in the gas is v=√γp/ρ =√γRT/M

4 (This one is the most difficult one, can anyone help me with it?)
(a)Derive the entropy chang: ΔS=Sf-Si=nRln(Vf/Vi)+nCvln(Tf/Ti) for all reversible processes that take the ideal gas from state i to state f.
(b) Please use this relation to calculate the change in the entropy for a free expansion process from V to 4V. Please also give the reason that you may do in this way.
(c)Derive this increase of entropy with statistical mechanics(using the Boltsmann's entropy S=klnW,where k is the Boltsmann's constant,W the multiplicity of the confriguration).Before doing this,please give explain.
(Hint:lnN!=N(lnN)-N,while N is large)
 
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  • #2
Here we don't help if you don't provide us with attempt to solutions and some relations/forumulas that you know.
 

1. What are thermal dynamics and why are they important?

Thermal dynamics is the study of how heat and energy transfer in physical and chemical systems. It is important because it helps us understand and predict how materials and systems will behave under different temperatures and conditions.

2. How can I approach solving difficult thermal dynamics questions?

The best approach to solving difficult thermal dynamics questions is to start by understanding the basic concepts and equations involved. Then, break down the problem into smaller, more manageable parts and use the relevant equations and principles to solve each part. It is also helpful to draw diagrams and make use of any given information or known values.

3. What are some common mistakes to avoid when solving thermal dynamics questions?

Some common mistakes to avoid when solving thermal dynamics questions include using incorrect units, not considering all the variables involved, and forgetting to account for energy conservation. It is also important to double-check calculations and make sure they are accurate.

4. How can I improve my understanding of thermal dynamics?

To improve your understanding of thermal dynamics, it is helpful to practice solving a variety of problems and to seek help from a teacher or tutor if needed. You can also read textbooks or watch online lectures to gain a deeper understanding of the concepts and principles involved.

5. Are there any real-world applications of thermal dynamics?

Yes, thermal dynamics has many real-world applications, such as in designing heating and cooling systems, predicting weather patterns, and understanding the behavior of materials in extreme temperatures. It is also important in fields such as engineering, chemistry, and meteorology.

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