| Emergent properties of water |
|
Water’s properties contribute to the suitability of Earth as an environment for life. These are water’s cohesive behavior, its ability to moderate temperature, its expansion upon freezing, and its versatility as a solvent.
|
Cohesion
Water molecules in the liquid phase interact with one another via cohesive forces, which are forces of attraction between molecules of a single substance. For water, the cohesive forces are hydrogen bonds. When water is in its liquid form, its hydrogen bonds are very fragile, about one-twentieth as strong as covalent bonds. They form, break, and re-form with great frequency. Each hydrogen bond lasts only a few trillionths of a second, but the molecules are constantly forming new bonds with a succession of partners. Thus, at any instant, a substantial percentage of all the water molecules are bonded to their neighbors, making water more structured than most other liquids. Collectively, the hydrogen bonds hold the substance together, a phenomenon called cohesion. |
| Previous | Next |
|
