Chemistry

Water Pollution * Sources of water pollution can be divide into two types – point sources and non – point sources. * Point sources are the easily identifiable sources of pollution, such as municipal and industrial discharge pipes. * Non – point sources are not easily identifiable such as agricultural off from farms, acid rain ... Read more

Air Pollution: Gaseous Pollutants * Pollution is the harmful effect on the environment that can prove fatal to all living organisms. * Pollutants can be solid, liquid or gaseous, and originated from human actions and natural sources. * Air pollution takes place in two different layers of the earth’s atmosphere – the Atmospheric pollution * ... Read more

Gaseous State: Gas Laws * Volume, number of moles, pressure and temperature are the four interrelated properties that describe the behaviour gases. * Boyle’s Law describes the relationship between pressure and volume. It states that volume is inversely proportional to pressure at constant temperature and number of moles. * Charles’ Law describes the relationship between ... Read more

Position of Hydrogen in the Periodic Table * Hydrogen is the first element in the periodic table. * The atomic number of hydrogen is one. * Hydrogen has only one electron in the k-shell of its atom. * Hydrogen has a dual nature; it resembles the alkali metal as well as the halogens. * Like ... Read more

Periodic Classification of Elements – History of Periodic Table * Dobereiner’s Law of Traids: In a traid, the atomic mass of the middle element is equal to the arithmetic mean of the atomic masses of the other two. * Newlands law of octaves: When elements are arranged in increasing order of their atomic weights, the ... Read more

Structure of Atoms – Structure of an Atom * An atomic number is the number of protons in an atom. * The arrangement of electrons in various energy levels of an atom is known as electronic configuration. * The maximum number of electrons in any energy level of the atom is given by 2n2. * ... Read more

Composition of Water * The chemical formula of water was established by S. Cannizzarro as H2O. * The process of decomposing water into its constituent elements called electrolysis of water. * Hydrogen and oxygen combine in the ratio of 2:1 by volume to from water. * The gravimetric or mass ratio of hydrogen to oxygen ... Read more

Physical and Chemical Changes – Physical and Chemical Changes * Change is all around us and happening constantly. Some changes are Physical and some are chemical. * Some changes affect only the physical properties of the substance that is undergoing change. Physical include things like shape, size, colour and state of matter. Physical changes are ... Read more