|Apr17-05, 09:34 AM||#1|
My chem book says that
Enthalpy = internal energy+pressure*volume
However it says that enthalpy for a particular state cannot be calculated. Only the enthalpy change can be calculated. This has me confused.
Aren't internal energy, pressure and volume calculabe for a particular state? Then why can't we calculate absolute enthalpy?
|Apr17-05, 11:14 AM||#2|
Enthaply is used to calculate how much energy is taken in or released by a reaction where bonds have been broken (well all reactions really need bonds to brake but still...).
Enthaply, however, also depends on the temperature (if I am correct) and ,thus, it is only possible to have an equation for the change.
This might help or checking the rest of these might as well.
The Bob (2004 ©)
|Apr17-05, 02:43 PM||#3|
It should be change in PV, or [tex] \Delta PV[/tex], the work in expansion against the atmosphere
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