Small city, BIG ammenities! That is Hidalgo, Texas. The City of Hidalgo is located on lands settled by Spanish -colonizer Jose de Escandon in 1749, as an adjunct to the new settlement of Reynosa, both part of colonial Spain until 1821. The desert settlement was mainly involved with cattle grazing for some 150 years.
When something changes phase from solid to liquid, or from liquid to gas, it takes energy to break the intermolecular interactions. These interactions between the water molecules are what make it solid. When you have ice, these interactions are strongest, which is why ice is hard.
DH=qp D H represents the difference between the enthalpy of the system at the beginning of the reaction compared to what it is at the end of the reaction: Enthalpies of Reaction. Heat and Enthalpy Changes. When a chemical reaction occurs in an open container most of the energy gained or lost is in the form of heat. Almost no work is done (i.e. nothing is being moved). Heat flows between the system and surroundings until the two are at the same temperature. 1  When a chemical reaction occurs in which the system absorbs heat, the process is endothermic (it feels cold). 2  When a chemical reaction occurs in which the system produces heat it is exothermic (it feels hot).