Chemistry is the scientific study of matter and its properties, composition, structure, and the changes that occur during chemical reactions.Â
It provides the foundation for understanding the world around us, from the structure of matter to the interactions between different elements. Here are some basic concepts.
Percentage Yield FormulaÂ
                   ActualÂ
Percentage Yield = -------------------------  Â
                 Theoretical yield x 100
              The mass of one atom of the element
Atomic mass formulaÂ
Atomic mass = -------------------------------------- = Eq. mass X valency   Â
             1/12 Mass of an atom of C-12
                  Eq. mass x Valency              6.4   Â
Alomic mass    =  ------------------------------------ =  ---------------------
                  Atomicity Specific heat (cal/g)   Specific heat (Cal/g)
Number of gram atoms formulaÂ
                            w(g)
Number of gram atoms = -------------------------------
                      Gram atomic mass (GAM)
                            w(g)
Number of gram molecules  = --------------------------
                          Gram Atomic massÂ
                                   w(g)
Number of gram equivalents=Â Â --------------------------------
                           Gram equivalent mass (GEM)
                           Atomic mass
Equivalent mass of an element = -----------------
                              Valency
                        Molecular mass of acid
Equivalent mass of an acid = -------------------------
                             Basicity
                        Molecular mass of base
Equivalent mass of a base = ------------------------------
                          Acidity
                       Mass of the element
Percentage composition= -------------------------------- *100
                     Molar mass of compound
              Mass of solute
   Mass = --------------------------------*100
               Mass of solution
Molarity formulaÂ
              WB * 1000Molarity = -------------------------
              MB* V (in ml)
Normality formulaÂ
             WB *1000Normality = --------------------
          EMB* V(in mL)
               WB *1000
Molality (m)= --------------------
              MB Wa (in g)
Mole fraction formulaÂ
                   NB            NAMole fraction XB = ------------- And --------------
                  NA + NB             NA +NB
Molecular mass= 2 x Vapour density
where, WB =Mass of solute, MB= Molecular mass of solute, WA =Mass ol solvent
Number of moles= Molarity * Volume
Number of equivalents =Normality * Volume
Molecular formula= n * Empirical formula
n = -----------------------------------
       Empirical formula mass
Structure of Atom formulaÂ
The radius of nucleus (R) = R0Â A1/3
Ro = Constant (= 1.33 x 10 -13 cm)
A= Mass number of atom
Maximum no, of spectral lines produced when an electron
Jumps from n ----> 1 = n(n - 1) / 2
Magnetic moment = (L{n+2)B.M)1/2
Spin angular momentum= ys(s+1)
Spin multiplicity= 2S+ 1
S=Sum of Spin Quantum numbers
Radial nodes=n- l-1; Angular nodes=l
Total no, of nodes = n -i