STD IX – WATER – ARCHIMEDES

WATER AS A UNIVERSAL SOLVENT

Water is called the universal solvent since it is capable of dissolving a variety of different substances more than any other liquid.

From a biological point of view, this is important for living organisms, as water is capable of transporting nutrients and minerals from the surrounding elements into their bodies and inside their bodies as well.

Water can dissolve more substances than any other compound because of its polar nature. The water molecules because of their composition – hydrogen with a positive charge on one side and oxygen with a negative charge on another, are able to attract other molecules easily.

Hydrated and anhydrous substances.

Water of crystallisation:

When crystals of certain salts are formed, they do so with a definite number of molecules of water that are chemically combined in a definite proportion. Water of crystallisation is defined as the number of water molecules, chemically combined in a definite molecular proportion, with the salt in its crystalline state. This water is responsible for the geometric shape and colour of the crystals.

Hydrated and anhydrous substances.

Hydrate: A substance containing water of crystallisation is called a hydrous substance or a hydrate. This water can be expelled, by heating, and then the salt is said to have become anhydrous.

Soft water and Hard water

Hard water

Hard water is the water that contains an appreciable quantity of dissolved minerals (like calcium and magnesium).

Soft water

Soft water is treated water in which the only ion is sodium. As rainwater falls, it is naturally soft. … On the other hand, soft water tastes salty and is sometimes not suitable for drinking.