hardness in classification of matter

All metals are hard except sodium and potassium, which are soft and can be cut with a knif..

The skeleton or its parts get preserved with the living matter completely disintegratin..

All around us are substances that are made of matter. Matter has mass and occupies some space. Different kinds of substances are made up of different matter. Matter can be thus classified in many ways. Two basic classifications of matter a..

A solid has certain characteristics: According to modern theory, the molecules of a solid are fixed in relation to each other. They vibrate in place, but do not wander around. This accounts for the fact that a solid keeps its own shape. Solids are usually crystalline. A solid is a crystalline subst..

Classification of Matter - All around us are substances that are made of matter. Matter has mass and occupies some space. Different kinds of substances are made up of different matter. Matter can be thus classified in many ways. Two basic ..

Introduction - Today the fact that all matter is made up of atoms is universally accepted. Realisation of the atomic constituents of matter began in 1828 when Scottish botanist Robert Brown observed a random ceaseless motion of pollen grains suspended in a liquid. Many macroscop..

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Water is said to be permanently hard when it contains sulphates and chlorides of calcium and magensium. Water becomes permanently hard when it passes over the rocks, which contain sulphates or chlorides of calcium and magnesium to form insoluble calcium bicarbonates or magnesiu..

The hardness of metals is due to the strength of the metallic bond. In general, the strength of a metallic bond depends upon: The greater the number of valence electrons for delocalisation the stronger is the metallic bond. Smaller the size of the kernel of metal atom, greater is th..

Removal of Temporary Hardness..