Final answer:
Compounds that dissociate in water are typically ionic, and they undergo a process called dissociation and hydration. Water, being a polar solvent, can dissolve both polar and ionic substances. Molecules with both polar and nonpolar parts are known as amphipathic.
Step-by-step explanation:
Compounds that readily dissociate in water are typically ionic. Ionic compounds in water separate into cations and anions, a process known as dissociation. When these ions are in solution, the polar nature of water molecules allows them to become hydrated, which means they become surrounded by water molecules in a process called hydration. This leads to the ions being evenly distributed in the water. An important point to note is that water is considered a universal solvent due to its ability to dissolve both polar and ionic substances, as well as a very limited amount of non-polar substances.
Molecules bearing both polar and nonpolar groups are referred to as amphipathic. Amphipathic molecules have regions that are hydrophilic, which interact with or dissolve in water, and regions that are hydrophobic, which do not dissolve in water.