Chapter 15 ? 2010, Prentice Hall Organic Chemistry, 7th Edition L. G. Wade, Jr. Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy Chaper 15 * Conjugated Systems Conjugated double bonds are separated by one single bond. Isolated double bonds are separated by two or more single bonds. Conjugated double bonds are more stable than isolated ones. Chaper 15 Chaper 15 * Heat of Hydrogenation of Conjugated Bonds For conjugated double bonds, the heat of hydrogenation is less than the sum for the individual double bonds. The more stable the compound, the less heat released during hydrogenation, Conjugated double bonds have extra stability. Chaper 15 Chaper 15 * Relative Stabilities twice 1-pentene more substituted Chaper 15 Chaper 15 * Structure of 1,3-Butadiene