Thermodynamics - know process, work and change in entropy. Final temperature?

In summary, the problem involves a 200-gram sample of dry air being heated isobarically, resulting in an increase of 19.2 J/K in entropy and 1.61x10^3 J of work done by expansion. To solve for the final temperature of the air, the equation dq=dq(Cv/Cp)+dw can be used, with dq=460.46 being found. However, the initial temperature is unknown, so the equation d\phi=dq/T cannot be used. To solve for the final temperature, the equation Tfinal-Tinitial = work can be used, and then the integral dphi=dq/t can be used to find the answer for Tfinal.
  • #1
HHveluj
5
0
So, the problem is:
A 200-gram sample of dry air is heated isobarically. Its entropy increases by 19.2 J/K and the work done by expansion is 1.61x103 J. Solve for the final temperature of the air.

Okay, since p=const => dq=CpdT thus instead of dq=du+dw we can write
dq=dq(Cv/Cp)+dw
can find dq=460.46
So i know dq,du,dw,d[tex]\phi[/tex], but how do I get final temperature? All I can find is dT but it's useless sine I don't know initial temperature.
And where do I put mass and how to use the d[tex]\phi[/tex]=dq/T formula? Looks like it will be needed here...

Thanks a lot in advance!
 
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  • #2
nevermind. solved it.
 
  • #3
Aw. I have this problem too and I'm stuck on it. :(
 
  • #4
Get Tfinal - Tinitial through work, then you can solve integral dphi=dq/t and get the answer for Tfinal.
 
  • #5
I have this problem too and i still do not understand how you can solve for T final if there is not an initial temp given.
 

1. What is thermodynamics?

Thermodynamics is a branch of physics that deals with the study of heat and its relation to energy and work. It explains how energy is transferred between systems and how it affects the behavior of materials and substances.

2. What is a process in thermodynamics?

A process in thermodynamics refers to the transformation or change of a system from one state to another. This can involve the transfer of heat, work, or both.

3. What is work in thermodynamics?

In thermodynamics, work is defined as the transfer of energy from one system to another. It can be done by applying a force on an object and causing it to move a certain distance.

4. What is entropy in thermodynamics?

Entropy is a thermodynamic property that measures the amount of disorder or randomness in a system. It is often associated with the increase of disorder in a closed system over time.

5. How is the final temperature determined in thermodynamics?

The final temperature in thermodynamics is determined by the conservation of energy principle. This means that the total energy in a closed system remains constant, so the final temperature is the point at which the transfer of heat and work have reached equilibrium.

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