Maria Elisa La Ferla (Group: 6B)
Is water really necessary for life? Discuss.
Necessity of water with reference to its physical properties
Properties of water:
As a solvent
Cohesion and surface tension
Specific heat capacity
Heat of Vapourisation and Heat of Fusion
Density and ice
Water is the most abundant substance in living organisms as it occupies around 60% to 95% of the fresh mass of an organism. It is an unusual substance with unfamiliar properties since it exists on earth in all three states, solid, liquid and gas. Water allows chemical reactions to take place inside all living things, and so it is important for a water molecule to have certain structures.
In a water molecule, both the hydrogen and the two oxygen atoms attract electrons, and therefore there is a form of electronegativity between the two different elements in the molecule. Due to this nature of water, a partial positive charge is carried on each hydrogen atom while a partial negative charge is carried on the oxygen atom.
For this reason, water is said to be a dipolar molecule owing to the face that it has two electric charges which are equal in size, but of opposite polarity, and separated by a short distance. Moreover, hydrogen bonds are found bridging one water molecule to another.
Water as a solvent
Due to its physical properties, water has a number of functions which enable life. Firstly, because of its capability to form hydrogen bonds, water is an excellent solvent. Water molecules collect near to any substance which has an electric charge. When an ionic or polar compound is found in water, it is surrounded by water molecules. The relatively small size of a water molecule, allows many water molecules to surround one molecule of...