Water (data page)

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Temperature dependence surface tension of water

Density of ice and water (en)

Phase diagram of water

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|Temperature dependence water ionization.svg]]|thumb]] Water (data page)

Water, a chemical compound with the formula H2O, is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. This data page focuses on the physical and chemical properties of water, along with its role in the environment and technology.

Properties

Water has unique properties that make it an essential compound for life. It is a polar molecule, with the oxygen atom having a slight negative charge and the hydrogen atoms a slight positive charge. This polarity allows it to form hydrogen bonds, which are responsible for many of its special properties, including its high surface tension, high boiling point, and ability to dissolve many substances.

Physical Properties

• Boiling Point: 100°C (212°F) at 1 atmosphere pressure
• Freezing Point: 0°C (32°F) at 1 atmosphere pressure
• Density: 1 g/cm³ at 4°C (39°F), density decreases when frozen
• pH: Pure water has a pH of 7, making it neutral

Chemical Properties

• Molecular Weight: 18.01528 g/mol
• Solvent Properties: Water is known as the "universal solvent" because it dissolves more substances than any other liquid. This property is crucial for the transport of nutrients and waste in biological organisms.

Distribution in Nature

Water covers about 71% of the Earth's surface, mainly in seas and oceans. Fresh water is found in rivers, lakes, and underground aquifers, but it constitutes only a small fraction of the Earth's total water supply.

Role in the Environment

Water plays a key role in the environment by regulating the climate through its large heat capacity and by transporting heat through the atmosphere and oceans. It is also essential for the water cycle, which includes processes such as evaporation, condensation, precipitation, and runoff.

Uses

Water is used in various ways, including as a drinking water, in agriculture for irrigation, in industry as a coolant or solvent, and in energy production in hydroelectric power plants.

Water Quality and Treatment

Water quality is crucial for health, agriculture, and industry. Treatment processes such as filtration, sedimentation, and disinfection are used to remove contaminants and make water safe for consumption and use.

Challenges

Access to clean water remains a challenge in many parts of the world, leading to water scarcity and pollution problems. Efforts to improve water management, conservation, and treatment are ongoing to ensure sustainable water resources for future generations.