Water, this simple naturally occurring binary compound is more precious than all the diamonds in the world. You may find this statement to be a hyper-exaggeration, but it is true, if one is stranded in the Sahara desert without water. There are many people around the world who struggle daily and walk miles just to fetch a pail of water.
What are the unique properties of water that make it so important? Why is it said that life can exist without oxygen, but it is extremely difficult for life to sustain without this naturally occurring liquid compound? Find out the answers here.
It is the major constituent of all life forms. More than 60% of all plants and animals is made up of water.
Adhesion and Cohesion
Water molecules are attracted to each other, and therefore, they show the property of cohesion. They are also attracted to molecules of other substances called adhesion. Water gets it property of adhesion due to its chemical structure. The positive charge from the hydrogen molecule at one end and negative charge from the oxygen molecules.
Each and every drop of water is attracted to other water molecules due to surface tension between them. In order to understand surface tension, let's see an example. When you see a drop of water fall from the rim of faucet, the drop won't fall immediately.
It will stretch itself very thin as much as possible, before falling down. As it falls, it will form a spherical shape and no other shape. This property is due to surface tension between the water molecules that allows them to stick to themselves.
Water has the ability to absorb heat and become hot. Thus, when you boil water, it will take really long to boil. Water tends to take in as much heat as possible from the surroundings and become hot itself. This property enables the huge amount of water in our oceans to act as reservoirs of solar heat. Thus, maintaining a balance of temperatures on earth.
When one places a 'hollow' straw in a glass of water, one will observe the capillary to climb up the straw. This happens when one water molecule moves into the straw, other molecules due to their adhesive properties, follow suit.
Thus, water moves up the capillary. The movement of water in the straw is restricted due to the size of straw and action of gravity. Water moves up higher, if the straw is thinner.
Water is made up of two molecules, hydrogen and oxygen. One oxygen atom is bonded to two hydrogen atoms and both the hydrogen atoms are bonded to each other through a covalent bond. The hydrogen atoms are attached to the oxygen atom on one side.
This results in water molecule having a positive charge due to presence of hydrogen atom. The other side of the water molecule is negatively charged due to the presence of oxygen atom. As opposites attract, water molecules are sticky and are attracted to each other (adhesion property).
A water molecule has neutral charge due to presence of equal number of electrons and protons. The property of polarity of water occurs due to the electrons that are distributed asymmetrically.
The electrons are drawn away from the hydrogen nuclei due to the force from oxygen nucleus. This leaves the nuclei of hydrogen with a slightly positive charge. Excess of electron density creates a weak negative charge in the oxygen atom.
The molecules of water are connected to each other transiently in a hydrogen bonded lattice. Water molecules are joined to four other water molecules in a temporary assembly called the 'flickering cluster' even at 37º C.
Those substances that can readily dissolve in water are called hydrophilic molecules. These substances are made of ions or polar molecules. These ions are attracted to water molecules due to the electrical charge effect. Each of the ions or polar molecules present on the solid substance is surrounded by water molecules and thus forming a solution.
Those substances with a majority of non-polar bonds and are insoluble in water are called hydrophobic molecules. This property is true especially in case of hydrocarbons that have C-H bonds. As water molecules are not attracted to these substances, they do not surround them and do not form a solution.
Due to the polar property of water, two adjacent water molecules form a linkage. This linkage is called the hydrogen bond that has 1/20th strength of a covalent bond. Thus, hydrogen bonds are strongest when there are three atoms present in a straight line.
More than 70% of earth's surface is covered with water. It is largely found in oceans and other large water bodies. Water is continuously recycled through the process of evaporation and transpiration, precipitation, run off, etc. Clean drinking water is very important for humans as well as other animals as well as plants.
- Water has highest surface tension compared to all liquids, except mercury.
- It expands on freezing, this is one of the unique properties that is seen in very few other substances.
- It will expand with temperature increase above 4º C.
- It has the highest latent heat of fusion and vaporization.
- It is slightly compressible, as its density is high.
- It is a universal solvent.
- It is one of the few inorganic liquid substances.
These properties show some of the importance of water in detail. This information will definitely help you learn more about the unique binary compound.