1) Water is a polar solvent due to difference in the electronegative values between the hydrogen and oxygen which sees the Oxygen end of the molecule having a slightly negative charge while the hydrogen end has a slightly positive charge. This allows water to dissociate to form positive and negative ions.
[tex]H_{2}O [/tex] ⇄ [tex]H^{+} + OH^{-} [/tex]
Because water is able to form positive and negative ions in solution and as such it is able to dissolve compounds because the negative and positive ions it possesses break the bonds of compounds and keep them apart. This is why it is a Universal Solvent and why it can dissolve solutes in the blood, be a medium of transport in plants, make up a large percent of cell cytoplasm and aid in aquatic environment survival.
2) Water because of its dipole is able to form hydrogen bonds which is where a highly electronegative atom in a molecule with a lone pair of electrons in this case the oxygen in water bonds with the hydrogen of another molecule.
a) this allows water to have a high specific heat capacity which means that a lot of heat energy is needed to change water by 1°C. This is because much energy is needed to break the hydrogen bonds in water. This allows water to maintain body temperature by absorbing energy in the form of heat in the body with there only being an incremental change in the temperature of the body.
b) Because of the hydrogen bonding between water molecules, water also possesses a high heat of vaporization which means that much energy is needed to convert 1kg of water from its liquid state to its gaseous state. With this being the case, water can act as a coolant by absorbing the heat from a body an remove it when it evaporates as it is in the case of sweat.
c) The hydrogen bonds also allow water at the surface to contract so that it occupies the least possible area. This sees where water forms a thin layer atop a water body. This allows for some objects to float atop the water and also allow some small animals to move across the surface of water often as an escape from predators.
Water also has a high cohesive and adhesive power and this attraction is more powerful than gravity. This allows water to move through capillaries and up xylem vessels in plants.
