The physical and the chemical properties of the water

 

The physical properties of the water 

 

It is very important to know that the water has a higher melting point , boiling point , and heat of vaporization than most common liquid . This fact indicates that there are strong forces of attraction between the adjacent water molecules .  

 

The Water exists in three states

The states of the water

You should know that the states of the water are the solid state ( ice ) , the liquid state ( the water ) , and the gaseous state ( the water vapour ) at the normal temperature . 

 

The water is a good polar solvent 

The water dissolves the most ionic compounds such as the table salt .

You notice that the water is a good polar solvent . So , It has a great ability to dissolve the most ionic compounds such as the table salt  ( sodium chloride ) . 

 

The water can also dissolve some covalent compounds such as the sugar that can form the hydrogen bonds with it . Some covalent compounds such as oil can not dissolve in the water as they can not form the hydrogen bonds with the water .

The water is a good polar solvent .

 

The Pure water boils at 100 degrees Celsius and freezes at 0 degrees Celsius

 

You should know that the high boiling point and the low freezing point of  the water is due to the presence of the hydrogen bonds between its molecules .

 

The water density decreases on freezing 

The ice floats on the water surface which helps the aquatic creatures to be alive .

It is very important to know that the density of the water in the solid state ( the ice ) is lower than its density in the liquid state as when the temperature of the water deceases than 4 degrees Celsius , The water molecules are collected together by the hydrogen bonds to form the ice crystals which  have the hexagonal shape , the large volume and the large number of spaces between them .

 

You should know that the ice crystals float on the water surface and this helps in the preservation of the life of the aquatic creatures  in it .

 

The water has high latent heat 

 

It is very important to know that the water has high latent  heat . So , it resists the change from a state to another . So , the water is used to extinguish the fires , as it consumes a large amount of the heat of the combustion media during its vaporization process .

 

The water has high specific heat 

 

You notice that the temperature of the human body does not change by changing the atmospheric temperature . The high specific heat of the water makes it absorb or lose the large amount of the heat without changing its temperature .

 

The chemical properties of the water  

 

The weakness of the water ionization

The water ionizes to give positive hydrogen ions and negative hydroxide ions .

You should know that the ionization is the process of converting the molecules of some covalent compounds into ions , And The pure water is considered from the weakly ionized that gives positive hydrogen ions and negative hydroxide ions .

 

The water has a neutral effect

The water has a neutral effect on the litmus paper .

You notice that the water has a neutral effect on the litmus paper as when it ionized , it gives equal numbers of the positive hydrogen ions ( which are responsible for the acidic property ) ,  and the negative ions ( which are responsible for the basic property ) .

 

The resistance of the water to decomposition 

 

You  should know that the water does not decompose into its elements ( hydrogen and oxygen ) under the normal conditions or even by the effect of the heat that helps to keep the aqueous solutions inside the cells of the living organisms .