structures of harming substances

Noble gases - All noble gases crystallize in ccp structure except helium which has hcp structure..

Molecular substance having nearly spherical molecules have closed packed arrangements. Examples: Solid H 2 has hcp structure, while solid CH 4 , HCl, H 2 S have ccp structure..

SO 2 is poisonous and irritates the respiratory system of animals and humans. A continuous exposure to concentration of 0.2 ppm lasting for 3-4 days or even 0.5ppm for full day has been reported to damage the lungs and increase the rate of mortality. In plants and grasses, SO 2 also produces ..

Pure and Impure Substances - All matter can be broadly divided into two major groups "Pure" and "Impure". The term 'purity' has quite a different meaning in chemistry than in our day-to-day life. Normally when we refer to pure water, pure milk, etc., what is implied is that the water, mil..

There are more than hundred elements around us. But, we do not find these elements in their native form. This is because most of these elements are highly reactive. They interact with each other to form simple or complex substances. Only elements with the noble gas configuration hav..

Introduction - The evidence of the electrical nature of matter preceeded the first theories about the structure of matter. In 1832, Michael Faraday discovered electrolysis. He gave the first important clue relating electricity to matter and about the electric nature of atoms. Faraday enun..

Each pollen grain is a haploid, unicellular mass of protoplast with a single nucleus. It is surrounded by a thick wall differentiated into two layers; the outer thick exine and the inner thin intine . The pollen grains reveal a wide range of microsculpturing of the exine under a scanning microscope..

The epithelial cells play an important role in the removal of unwanted and harmful substances from the bod..

The major problem that the atmosphere is being subjected to is pollution. In India, about 100 million tons of pollutants are being added to the atmosphere annually. This figure is likely to go up in future. Polluted air is harmful to man and the biosphere on the whole, as well. This probl..

Coolants are substances used to remove and transfer the heat produced to the surrounding. It passes this heat over to water in a heat exchanger. This results in superheated steam, which drives a turbine coupled to an electric generator. The whole reactor is protected with concrete walls ..