Water is an inorganic chemical compound with the chemical formula is H2O. Under standard conditions for temperature and pressure (STP), water is known to exist as a colourless, odourless, and tasteless liquid. However, water is known to exist in all three physical states on the planet (solid, liquid, and gaseous). The three states of water are ice (solid), water (liquid), and water vapour (gas). Water is also the primary constituent of the Earth’s hydrosphere. It can also be noted that water covers over 70% of the Earth’s surface. Some important properties and uses of water are listed in this article.
Hydrogen Bonding in Water
Each molecule of water contains two hydrogen atoms and one oxygen atom. The hydrogen atoms are singly bonded to the oxygen atom via covalent bonds. However, due to inequalities in the electronegativities of the bonded atoms, the covalent bond becomes polarized. This causes the oxygen atom to develop a partial negative charge and the hydrogen atoms to develop a partial positive charge. When a hydrogen atom (with a partially positive charge) belonging to one water molecule interacts with an oxygen atom belonging to another water molecule (and holding a partially negative charge), the type of chemical bond formed is commonly referred to as a hydrogen bond. Thus, water is subject to intermolecular hydrogen bonding between oxygen and hydrogen atoms.
Properties of Water
A few notable properties of water are listed below.
- The molar mass of water is approximately equal to 18.015 grams per mole.
- The appearance of water changes based on the physical state it exists in. For example, it exists as a white, crystalline solid in the form of ice. It also exists as a colourless/slightly blue liquid and as a colourless gas.
- The density of water can be roughly approximated to 1 kilogram per litre.
- The melting point of water corresponds to 0 degrees celsius whereas the boiling point of water is roughly equal to 100 degrees celsius (at STP).
- Pure water is not a great conductor of electricity. However, when certain minerals and ions are dissolved in it, water becomes a great conductor of electric currents.
- Pure water is known to be a neutral substance with a pH of approximately 7.
- Water is also known to exhibit capillary action since it features relatively strong adhesive and cohesive forces. The strong cohesion exhibited by water molecules can be explained by the presence of intermolecular hydrogen bonds.
Uses of Water
Water is absolutely essential for life to survive. Without drinking water, life would cease to exist. In fact, water is often referred to as the “soup of life”. A few other important uses of water are listed below.
- Water is widely used in the daily lives of humans for cooking, cleaning, bathing, and washing clothes.
- The processing of wood in the production of paper also involves the use of water.
- In fuel cells, dihydrogen is reacted with oxygen in the presence of a suitable catalyst to yield water and energy.
- Water is also used in the agriculture industry for the irrigation of crops.