Water
What are the properties of water?
Waterglossary term (opens in a new window)’s properties make it ideal for sustaining life on Earth:
- A water molecule contains one oxygen atom bonded to two hydrogen atoms via polar covalent bonds.
- The polarity of the covalent bonds causes oxygen to be slightly negative and hydrogen to be slightly positive. Thus, water is a polar molecule.
- The polarity of water molecules causes them to bind to one another through hydrogen bonds, which connect the hydrogen of one water molecule with the oxygen of another.
- Water (H2O) molecules dissociate into hydronium (H3O+) and hydroxide (OH–) ions.
- Water is one of the few substances that exist in all three states of matter on Earth’s surface.
- Water is cohesive, which refers to the fact that hydrogen bonds hold water molecules together.
- Water is adhesive, which means that it can also stick, through hydrogen bonds, to other substances.
- Water has a high surface tensionglossary term (opens in a new window), which means that it is difficult to break the surface of water.
- Water is a versatile solventglossary term (opens in a new window), meaning that many substances on Earth can dissolve in water.
- Water is unique from most substances in that it expands upon freezing. Solid water in the form of ice is less dense than liquidglossary term (opens in a new window) water.
- Water has a high specific heatglossary term (opens in a new window) capacity. It takes a relatively large amount of energy to change the temperature of water.
- Due to its high specific heat, water can store energy from the air around it. Water absorbs energy from warmer air and releases energy into cooler air.
- Water is able to moderate the temperature of surrounding air, keeping climates within a suitable range for living things.
