Heat content as a state function?

Click For Summary
SUMMARY

The discussion centers on the concept of heat content as a state function, specifically addressing a video presentation where the instructor claims that adding heat (q=2) to a thermodynamic cycle results in an increment of heat content. Participants highlight the contradiction in the instructor's assertion that heat can be incremented while also stating that heat equals work (Q=W), which implies no change in internal energy (ΔU=0). The consensus is that the instructor's explanation is flawed, as it overlooks the implications of energy conservation in thermodynamic cycles.

PREREQUISITES
  • Understanding of thermodynamics principles, particularly the first law of thermodynamics.
  • Familiarity with state functions and path functions in thermodynamic systems.
  • Knowledge of internal energy and its relationship with heat and work.
  • Basic grasp of thermodynamic cycles and their implications on energy transfer.
NEXT STEPS
  • Research the first law of thermodynamics and its implications for heat and work.
  • Study the differences between state functions and path functions in thermodynamics.
  • Explore examples of thermodynamic cycles and analyze energy conservation within them.
  • Watch educational videos on thermodynamic principles to clarify common misconceptions.
USEFUL FOR

Students of thermodynamics, educators teaching energy concepts, and professionals in engineering fields seeking to deepen their understanding of heat transfer and energy conservation principles.

firecool
Messages
11
Reaction score
0


at 3:30 he introduces heat content to show why it can't be a state variable. he says that if q=2 is added to the cycle everytime you go around the cycle the heat content would be incremented by 2. but as heat=work shouldn't that extra 2 be lost as work and at point 1 you always have hc=5? watch the video to make sense of my question.. :)
 
Last edited by a moderator:
Science news on Phys.org
firecool said:


at 3:30 he introduces heat content to show why it can't be a state variable. he says that if q=2 is added to the cycle everytime you go around the cycle the heat content would be incremented by 2. but as heat=work shouldn't that extra 2 be lost as work and at point 1 you always have hc=5? watch the video to make sense of my question.. :)


Yes, I caught that error also.
It clearly says, Q=W. which means all added heat is converted into work, as a result there is no change in internal energy, (delta)U=0.
Then why did he say, Q is incremented in every cycle. He should have said, practically (delta)U would never be zero.

Who is this guy (the teacher), anyway?
 
Last edited by a moderator:

Similar threads

Undergrad Thermodynamic functions and state variables
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Entropy change due to heat transfer between sources
  • · Replies 15 ·
Replies
15
Views
3K
Undergrad Extremely strange consequence of the speed of heat value
  • · Replies 19 ·
Replies
19
Views
3K
Graduate Tricky heat calculation from the 1850s
  • · Replies 4 ·
Replies
4
Views
1K
Heat content as a state function?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Enthelpy and Heat State Functions
  • · Replies 1 ·
Replies
1
Views
5K
Thermodynamic Cycle -- Work done as a function of Heat absorbed
  • · Replies 3 ·
Replies
3
Views
2K
Graduate Ballentine on the "multicomponent state function"
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Radon progeny content in activated charcoal canisters
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad Fin area and heat transfer direction
  • · Replies 6 ·
Replies
6
Views
2K