The common name for the chemical compound H2O is water. Water is essential for all known forms of life and is often referred to as the “universal solvent” due to its ability to dissolve a wide range of substances. It exists in three states: liquid, solid (ice), and gas (water vapor). Water covers about 71% of the Earth's surface and is crucial for various processes, including metabolic functions, climate regulation, and as a habitat for numerous organisms.