State and explain with examples; 1; Empirical Formula Such a formula which give smallest whole ratio between the atoms or ions of a compound. ¥ the term empirical means determine by experiment and observation. ¥ As to determine the formula of an unknown compound, first the whole number ratio of moles(atoms) of elements in compound is determined by experiment and calculation, therefore it is called empirical formula’ ¥ Empirical formula of benzene is CH and that of glucose is CH2O. ¥ All ionic compounds are represented by their empirical formula. Molecular Formula: The formula which shows the exact number of atoms in a molecule of a compound. ¥ empirical formula is the multiple of empirical formula while the multiple n is the ratio b/w the molecular mass and empirical formula mass. ¥ M.F = n( E.F) and n= M.wt/E.F. wt ¥ If the value of n = 1, then compound has the same empirical and molecular formula. ¥ Molecular formula of benzene is C6H6 and that of Glucose is C6H12O6. ¥ Water, Methane and ammonia has the same M.F and E.F. i.e. H2O, CH4 and NH3. Compound Molecular Formula Empirical Formula Benzene C6H6 CH Acetic Acid C2H4O2 CH2O Glucose C6H2O6 CH2O Methane CH4 CH4
Posted on: Fri, 19 Dec 2014 09:27:07 +0000