Difference between enthalphy and heat?

  • Thread starter asdf1
  • Start date
  • #1
734
0

Main Question or Discussion Point

in my thermodynamics textbook, enthalphy=U+PV
and (delta)heat=(delta)U+(delta)PV
those 2 look the same...
can anybody explain the difference?
@@
 

Answers and Replies

  • #2
Q_Goest
Science Advisor
Homework Helper
Gold Member
2,974
39
Hi asdf1. Take a look at your book again, I think you've taken it out of context. For example, flow through a pipe where heat is added or removed between two points in the pipe is a process in which the heat added/removed is equal to the enthalpy change in the fluid. On the other hand, for the situation where heat is added to a sealed container (ex: a pressurized tank), the amount of heat added or removed is equal to the change in the fluid's internal energy.
 
  • #3
hotvette
Homework Helper
988
3
I was taught that enthalpy was a property of a substance. Heat is a transport phenomenon only (i.e. transfer of energy) and that there is no such property as heat.
 
  • #4
GCT
Science Advisor
Homework Helper
1,728
0
at constant pressure with only expansion work the enthalpy of the substance does equal to the heat pertaining to the situation, that is [tex]q_p [/tex]
 
  • #5
734
0
thanks!!! :)
 

Related Threads for: Difference between enthalphy and heat?

Top