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How do hydrogen bonds affect the behavior of liquid water?
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water
Water is the most plentiful compound on Earth and is essential to life. Although water molecules are simple in structure (H2O), the physical and chemical properties of water are extraordinarily complicated.
Hydrogen bonds significantly influence the behavior of liquid water, primarily by dictating its physical properties and structure. Because water molecules are polar, the hydrogen atoms of one molecule are attracted to the lone-pair electrons of the oxygen atom on an adjacent molecule, forming weak hydrogen bonds.12
These bonds have several critical effects:
- State and Boiling Point: Hydrogen bonding is responsible for water existing as a liquid at normal temperatures; given its low molar mass, water would otherwise be expected to be a gas. The thermal energy required to break these bonds explains why water has a much higher boiling point than analogous compounds like hydrogen sulfide.34
- Molecular Structure: In the liquid state, water molecules form a dynamic, polymeric structure of aggregates that continually break and reform. This short-range order contributes to water's high viscosity and surface tension.12
- Thermal Properties: Water has an exceptionally high heat capacity and latent heat of vaporization because energy is required to break hydrogen bonds during phase changes, allowing water to act as a vital thermal buffer in the environment.5