1. The problem statement, all variables and given/known data I am having a bit of trouble grasping the idea and definition of enthalpy. I was wondering if someone could help. Am I correct in saying that a change in enthalpy only occurs if there is no temperature change? i.e. during a phase change/chemical change at constant temp? Thus since there is no change in temperature, there is no change in kinetic energy. The change in enthalpy is equivalent to a change in potential energy for the molecules involved as they separate/bond. For some reason I was confused because I thought that enthalpy was "the total kinetic and potential energy of the system" as defined in my textbook, but if temperature cannot change, by definition kinetic energy cannot change right? Can someone let me know whether or not my assumptions about temperature change are correct?