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The entropy of a hypothetical pure, perfect, crystalline sustance at absolute zero temperature is zero.

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xenon trioxide

A colorless, nonvolatile solid, XeO3, explosive when dry: in solution it is called xenic acid.

Nonbonding Orbital

A molecular orbital derived only from an atomic orbital of one atom, lends neither stability nor instability to a molecule or ion when populated with electrons.

Theoretical Yield

Maximum amount of a specified product that could be obtained from specified amounts of reactants, assuming complete consumption of limiting reactant according to only one reaction and complete recovery of product.


We breathe 24 hours a day, 7 days a week, consuming about 25 kg of air every day. It turns out that we practically predetermine our health by the air we breathe.

Law of Conservation of Energy

Energy cannot be created or destroyed, it may be changed from one form to another.


An algebraic increase in the oxidation number, may correspond to a loss of electrons.


The interaction of orbitals on different atoms in the same region of space.


An atom or a group of atoms that carries an electric charge.

Dispersed Phase

The solute-like species in a colloid.


Discovered : by Henry Cavendish in 1766.
Isolated in London, UK.
Origin : The name is derived from the Greek ‘hydro genes’, meaning water forming.
Description :A colourless, odourless gas that burns and can form an explosive mixture with air. It is currently manufactured from methane gas, but is also produced by the electrolysis of water and aqueous salts. The gas is used to make such key materials as ammonia, cyclohexane and methanol, which are intermediates in the production of fertilisers, plastics and pharmaceuticals. Some see hydrogen gas as the clean fuel of the future - generated from water and returning to water when it is oxidised. Hydrogen-powered fuel cells are increasingly being seen as pollution-free sources of energy.