
#37
Jul2611, 04:54 PM

PF Gold
P: 11,012





#38
Jul2711, 02:53 AM

P: 253

but as this goes true in mine example i still am looking for an answer from DALESPAM 



#39
Jul2711, 02:54 AM

P: 253

ANSWER TO THIS
well,thanks for this easy example,as seen in this example that the average K.E of molecules goes down both in air and water,but in this context the entropy of system as a whole cannot be connected to temperature,in a sense"the place with high entropy will have more energy". to my knowledge that is true but the example you have presented here is an exception? 



#40
Jul2711, 07:58 AM

P: 7

Hi,
A quick question from someone who don't know how entropy works Why do molecules in the air have more enthropy than those in the water? I thought that "entropy" is the amount of energy that can do useful work. Aren't the evaporated molecules in the second stage after doing their work. Thank you very much. 



#41
Jul2711, 10:26 AM

P: 253





#42
Jul2711, 10:32 AM

P: 253

"consider a box containing 4 molecules all with K.E of 40(in any unit),the molecules are bouncing back and forth between the opposite walls,now suppose there is another box that contains same number of molecules with K.E of 10 each but they deprive of the condition of being oscillatory(as in previous case) ,so they have a randomized nature, which will be perceived as a state of more disorder though it has less average K.E. 



#43
Jul2711, 11:53 AM

P: 7

Umm...ok I understand what you are saying...
But how does this coincide with: "Entropy is a thermodynamic property that can be used to determine the energy available for useful work in a thermodynamic process..." (Wiki)? Thanks. 



#44
Jul2711, 02:31 PM

P: 68

Uh oh! The problem with OP is that he is constructing a hypothetical experiment that will clash with the time tested laws of thermodynamics. Assuming that OP talks about a closed system, let's sit and explain this once he obtains the results that he assumed above! :P




#45
Jul2711, 02:35 PM

P: 68

[itex]\Delta[/itex]G=[itex]\Delta[/itex]HT[itex]\Delta[/itex]S where [itex]\Delta[/itex]G is the useful energy available to do work [itex]\Delta[/itex]H is the enthalpy change in the process T equals the temperature in Kelvins [itex]\Delta[/itex]S relates to the change in enthalpy. Always remember that a negative value of [itex]\Delta[/itex]G gives us a spontaneous reaction! 



#46
Jul2711, 08:27 PM

P: 7

Not exactly what I asked but it helped me to figure out, :P
Another quick question When gaseous particles move due to their heat/energy, their motion would be endless if they wouldn't collide with anything? If so, then wouldn't that mean that potential energy turned into work, meaning no entropy? Thx. PS. How do you say it, "collide in something" or "collide with something"? 



#47
Jul2711, 09:28 PM

Mentor
P: 16,472





#48
Jul2811, 06:27 AM

P: 253

i think i have a situation where my assertion could get false "consider a box containing 4 molecules all with K.E of 40(in any unit),the molecules are bouncing back and forth between the opposite walls,now suppose there is another box that contains same number of molecules with K.E of 10 each but they deprive of the condition of being oscillatory(as in previous case) ,so they have a randomized nature, which will be perceived as a state of more disorder though it has less average K.E. Old Y, 11:53 AM 



#49
Jul2811, 03:58 PM

Mentor
P: 16,472





#50
Jul2911, 07:51 AM

P: 253





#51
Jul2911, 11:04 AM

Mentor
P: 16,472

There is not enough information given. The entropy of a gas depends on other things besides just the temperature (and I don't know how to calculate the entropy of a solid):
http://hyperphysics.phyastr.gsu.edu...entropgas.html However, given the right conditions for the other variables (e.g. a large volume) then it is certainly possible for the lowtemperature gas to have more entropy than the hightemperature solid. Given other conditions (e.g. a small volume) then it is possible for the solid to have more entropy. This is why sublimation occurs more at low pressure than at high pressure. 



#52
Aug111, 10:22 AM

P: 253

you described well for my original question,thanks just last think that still is doubtfuldoes SLOT was verified in my original question,it was clear that the temperature of water in bucket and in air both goes down,but what about entropy? 



#53
Aug111, 10:56 AM

Mentor
P: 16,472




Register to reply 
Related Discussions  
The entropy of the universe? (attempts to define gravitational entropy)  Cosmology  22  
Show how the Boltzmann entropy is derived from the Gibbs entropy for equilibrium  Advanced Physics Homework  4  
How is the entropy of the universe increasing when entropy is simply transferred?  Introductory Physics Homework  5  
String entropy and black hole entropy  Beyond the Standard Model  3  
minimize entropy of P == maximize entropy of ???  Set Theory, Logic, Probability, Statistics  2 