CHEM野,關於heat

enthalpy change (delta H) 同 change in internal energy (delta U)有咩分別
(delta U)=(delta H)-work energy (the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.)

咁姐係enthalpy change係講緊open system做既reaction既熱能轉變?
It should be closed system (can gain or lose energy but not matter) rather than open system (can gain or lose both matter and energy)

其中既work done in the surroundings又係咩
the energy for expansion in the reaction