propertieswater

Water is a chemical compound with formula H2O, consisting of two hydrogen atoms covalently bonded to one oxygen atom. The molecule is bent with an angle about 104.5 degrees; O-H bonds are polar, giving water a dipole moment.

Water's physical properties include its status as a liquid at ambient conditions, and its colorless, tasteless, and odorless nature in pure form. Its density is about 1.000 g/cm3 at 4°C, while ice is less dense than liquid water, causing ice to float. Water exhibits cohesion and a notable surface tension of roughly 72 mN/m at room temperature. It has a high heat capacity (approximately 4.18 J/g°C) and a high heat of vaporization (about 2260 J/g), and a dielectric constant around 78.5.

As a solvent, water is highly effective for many ionic and polar substances due to its polarity and hydrogen-bonding network. It supports a wide range of chemical reactions and biological processes. Water undergoes autoprotolysis: 2 H2O ⇌ H3O+ + OH−, giving rise to a neutral pH near 7 at 25°C, though actual pH varies with temperature and impurities.

Phase behavior includes a melting point of 0°C and a boiling point of 100°C at one atmosphere, with a density maximum near 4°C. Water expands upon freezing, and the system’s critical point lies at about 374°C and 218 atmospheres.

Natural water contains dissolved minerals and impurities that affect conductivity and taste, producing categories such as hard water. Variants include heavy water (D2O), which is chemically similar but exhibits different physical properties. Water serves as the principal medium for environmental, geological, and biological processes.