Composition of Water

The chemical formula of water is H₂O, which consists of two hydrogen atoms bonded to one oxygen atom.

1. Molecular Structure

• Covalent bonds: hydrogen and oxygen atoms held together by shared electrons, forming a stable molecule.
• Polar Molecule: Water has a positive charge near the hydrogen atoms and a negative charge near the oxygen atom.

2. Properties Due to Composition

• Cohesion and Adhesion: Water molecules stick together due to hydrogen bonding, leading to high surface tension and capillary action.
• High Specific Heat: Water absorbs significant heat before it gets hot, regulating environmental and biological temperatures.
• Solvent Abilities: Water is the "universal solvent." It can dissolve more substances than any other liquid due to its polarity.

3. States of Water

• Solid (Ice): Water expands and becomes less dense upon freezing, allowing ice to float on liquid water.
• Liquid: Water is fluid in this state, conforming to the shape of its container.
• Gas (Water Vapour): Water vaporises into the atmosphere, contributing to the water cycle when heated.

We use water in large quantities. Water on the earth is regulated through the water cycle. The water vapour formed from oceans is the main source of water in the water cycle. It gets converted into rain, creating freshwater sources on earth.

1. Evaporation: Water from oceans, rivers, and lakes heats up by the sun, turning into vapour or steam that rises into the air.
2. Condensation: Water vapour cools in the sky, forming tiny droplets that come together to form clouds.
3. Precipitation: When clouds become too heavy, water falls to Earth as rain, snow, or hail, depending on the temperature.
4. Collection: Water gathers in rivers, lakes, and oceans, with some seeping into the ground to become groundwater.