The Physical Properties of Water

Molecule of water H₂O. The molecule of water consist of two atoms of hydrogen and one atom of oxygen. (Source: © peterschreiber.media / stock.adobe.com)

Molecule of water H₂O. The molecule of water consist of two atoms of hydrogen and one atom of oxygen.

Molecule of water

Water is a chemical compound made of hydrogen and oxygen.

At normal temperature and pressure conditions, it is a colourless, clear and odourless liquid.

In nature, it is found in three states:

  • solid — ice and snow
  • liquid — water
  • gas — water vapour
Molar mass 18.01528 g/mol
Melting temperature 0 °C
Boiling temperature 100 °C
Density 0.99997 g/cm³ (3.98 °C/ liquid)
Viscosity 0,001 Ns/m2
Refraction index 1.33
Critical temperature 374 °C
Critical pressure 22,140 kPa
Surface tension 0.073 N/m (20 °C)
Sound velocity, roughly 1,460 m/s
Specific heat coefficient 4,184 J/(kg*K) (liquid at 20 °C)

Water is used predominantly in its liquid state. (Source: © silver-john / stock.adobe.com)
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At normal temperature and pressure, water is a colorless, clear and odorless liquid. (Source: © alipko / stock.adobe.com)
The boiling point of water is determined by atmospheric pressure. (Source: © Michael Rolands / stock.adobe.com)
Water in its solid state — ice. (Source: © somchaij / stock.adobe.com)
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