A method of calculating atomic and molecular structure directly from the first principles of quantum mechanics, without using quantities derived from experiment (such as ionization energies found by spectroscopy) as parameters. Ab-initio calculations require a large amount of numerical computation; the amount of computing time required increases rapidly as the size of the atom or molecule
Solubility product: The product of concentrations of ions in saturated solution of an electrolyte at a given temperature is constant and is known as solubility product. For silver chloride, the equilibrium is formulated as follows. Undissolved salt ⇋ ions in solution AgCl(s) = Ag+(aq)+ Cl (aq) K = [Ag+][Cl–]/[AgCl] The concentration of the undissolved salt
Le-Chatelier principle: if an equilibrium system is subjected to a change, reaction will occur in such a way as to counter act the imposed change. Example. Manufacture of Ammonia: N3 (g) + H2(g) → 2NH3(g) ; ΔH = -93.6kJ. (i) Effect of pressure: The increases in pressure causes the-equilibrium to shift from left to right.