1. N

    Drinking bird temperature

    In a drinking bird, water from the wet on the outside of the head evaporates, causing the vapor inside the head of the bird to cool. This reduces the pressure of the vapor at the top, allowing the higher pressure in the lower bulb to push up the column of liquid. But the bird's body...
  2. Screwed

    Doubt with a calculation of the entropy of the surroundings.

    If we have an exercise like this: "Two moles of a perfect diatomic gas evolve from state 1 to state 2 through an irreversible process. In this process, the gas starts from a molar volume of 0.04 m3 / mol and 100 K to have a temperature of 500 K keeping the pressure of the system constant...
  3. X

    Question on entropy, please help me. urgent, thanks!!!!

    Closed. Question answered
  4. S

    The entropy change of solids and incompressible liquids

    This was asked as an addendum to another thread so I have started it as a new thread. I'm sorry but this is not correct since the temperature of the anchor varies during the cooling. In any case you should have started a new thread for this. I will do this for you and we can continue the...
  5. C

    Determine the increase in entropy

    A 60 kg mass is dragged horizontally over a distance of 10 m across the floor. The friction coefficient between the mass and the floor is 0.2. Determine the entropy increase of the surrounding atmosphere which is at 25 °C.
  6. A

    Ideal Gases as a model/ entropy where to start.

    (a) Using ideal gases as a model, show that the increase of entropy of n moles of a gas heated at constant pressure from a temperature T1 to a temperature T2 is ΔS = nCpln(T2/T1) (b) Show that the increase of entropy of a gas heated at constant volume from a temperature T1 to a...
  7. avito009

    Why entropy is more if heat is more?

    As we know what heat is. Heat is molecules having more kinetic energy. Kinetic energy increases as an object gets hotter. So hotter object has more energy i.e kinetic energy. So with more energy there are more possible arrangement of the molecules so entropy is more. Does this mean as an...
  8. avito009

    Why does Entropy always increase?

    Answer: If there's one right way to put something together, there are many wrong ways to do it. For example, if you pick up all the pieces of a jigsaw puzzle that you accidentally dropped on the floor and quickly put them right side up on the table, you don't expect the puzzle to be put together...
  9. H

    Question about Entropy of a VDW gas

    Problem: There is a piston that is filled with 4 mol of a vdw gas and is locked in place at 1 atm and 50L. It is then released and compresses the gas to 4L. The piston is in a large bath so the temperature remains constant. Find the entropy of the universe for this. a=4 L^2 atm mol^-2 b=0.03 L...
  10. T

    entropy quantification from T and V

    The first image derives macro to micro formula relation for T change for entropy. The other image derives micro to macro formula relation for V change. I will try to explain my problem: I get both theese derivations. Isolated they both relate entropy quantifiably from macro to micro and vice...
  11. T

    entropy def in site about tropical cyclones

    The formulas for entropy is taken from this site: Lecture 1: Observed characteristics The question is also in the attachment along with the formulas that I wonder about.
  12. A

    How can increased entropy accompany decreased heat capacity?

    Hi everyone, I've been pondering a problem for some time and text books have not been helping. I wonder if anyone can help me with it please. When a liquid boils, the heat capacity of the resulting gas is lower than that of the preceding liquid, on account of the loss of vibrational...
  13. S

    Calculating change in entropy?

    Im looking at using what we call Tds relations Tds = du+PdV and apparently integrating this will get the change in entropy. I dont know how to do this and how it would work? Where do you substitute in values for pressure, temp etc. Could someone please shed some light on this? I also...
  14. S

    How to calculate the change in entropy for a non ideal gas?

    Im looking at using what we call Tds relations Tds = du+PdV and apparently integrating this will get the change in entropy. I dont know how to do this and how it would work? Where do you substitute in values for pressure, temp etc. Could someone please shed some light on this? I also...
  15. S

    Calculating change in entropy??

    I know how to calculate the change in entropy for ideal gases however im stuck on how to calculate it for non ideal gases ie. real gases. Is there a formula for this?? Any help would be appreciated :)
  16. F

    Energy efficiency C02 store with throttle valve

    Hi, Is 3 weeks that I am trying to solve this problem, and I don't know if anyone ever attempted before. I have a canister containing co2 at saturated state. I drain co2 from the bottle to a throttling valve where it will make its isenthalpic transformation. lets assume that the store is...
  17. T

    defining entropy with heat instead of work?

    From what I understand, in the Carnot cycle summing qi/Ti for each step results in zero, thus indicating a new state function, entropy = qrev/T. But since dE = 0 = q+w, then q = -w, and looking at the equations derived from the cycle summing wi/Ti for each step should also result in zero. So why...
  18. W

    Thermodynamics: redefine work and heat

    I'm a retired engineer with a different approach to thermodynamics (i.e. energy transfer). Suppose we refine some of terms in thermodynamics based on the follow statements: 1. All energy has two components: work energy and heat energy. 2. Work is the change in work energy which is equal to the...
  19. B

    A problem on entropy

    Help required to solve physics homework problem A current of 4 A passes through a 60 ohm resistor for 5 min. The resistor is cooled by the continuous passage of fast running water (enough water so that its temperature essentially remains constant). The room temperature is 290K. Then how to...