CHEM 1A03 Chapter Notes - Chapter 9: Iron(Iii) Oxide, Ammonium Nitrate, Boltzmann Equation

• School: McMaster University
• Department: Chemistry
• Course: CHEM 1A03
• Professor: David Brock

Document Summary

Iron reacts with oxygen makes iron (iii) oxide, this reaction is spontaneous because it requires no additional energy. At temperatures above 0 degrees, ice will spontaneously melt into water. Non-spontaneous processes require the system to be acted on by an external agent, such as the input of energy. A reaction will naturally proceed towards reactants or products, whichever is more stable or lower in energy. However, this does not tell us anything about how long it will take. A spontaneous reaction can be rapid (exploding hydrogen balloon) or slow (many years, diamond to graphite). A general observation is that many reactions that are spontaneous liberate heat, so many spontaneous reactions are exothermic. There may be some relationship between enthalpy and spontaneity, because of the state change from solid to liquid is spontaneous. For example, instant cold packs that cool so quickly because of solid ammonium nitrate dissolving into water is endothermic and absorbs heat.