Is the process of melting endothermic or exothermic? What evidence supports the answer?
Ice melts at 0 oC. Energy transfer from the surroundings to the ice as it melts. Melting is endothermic. To understand why, think about what happens at the molecular level when a solid, such as ice, changes to a liquid. In ice, the molecules are all held in fixed places by the intermolecular forces (hydrogen bonds). When a solid melts the molecules have enough energy to vibrate fast enough to break free from their fixed positions. Breaking the hydrogen bonds needs energy; bond breaking is endothermic. Rev Risk assessment Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website. For further guidance see our tutorial on Risk Assessment.
