hydrogen bonding in water

• Hydrogen bonding


  A fundamental property of water
• Water is of the utmost biological importance
• It is the medium in which all metabolic reactions take place in cells
• Between 70% to 95% of the mass of a cell is water
• Water is so fundamental to life that astronomers look for signs of water on other planets and moons, as indicators of possible extra-terrestrial life
• As 71% of the Earth's surface is covered in water it is a major habitat for organisms
• Water


  Composed of atoms of hydrogen and oxygen
• Covalent bonding in water

  One atom of oxygen combines with two atoms of hydrogen by sharing electrons
• Although water as a whole is electrically neutral, the sharing of the electrons is uneven between the oxygen and hydrogen atoms
• Dipole


  Separation of charge due to the electrons in the covalent bonds being unevenly shared
• Water is a polar molecule
• Hydrogen bonds


  Form between the positive and negatively charged regions of adjacent water molecules
• Hydrogen bonds are weak, when there are few, so they are constantly breaking and reforming
• However, when there are large numbers present they form a strong structure
• Hydrogen bonds cause many of the properties of water molecules that make them so important to living organisms
• Hydrogen bonds between water molecules

  • Diagram
• The polarity of water molecules allows hydrogen bonds to form between adjacent water molecules