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SAI International School
                                                         Class-IX

                                                 Subject- Chemistry
                                            Topic-Atoms and Molecules
                                   Topic-Numericals based onMole concept

                                                      Lesson Note
               Recaptulation:



                                                      6.022 X10 23   number
                                                       of particles( ions,
                                                       atoms, molecules)





                                                             1

                                                           mole
                                             Gram                          Gram
                                           molecular                      atomic
                                           mass of a                    mass of the
                                           substance                     element

               Avogadro’s Number:  NA

               Number of Moles: n
               Given number of particles: N
               Molar mass: M

               Given mass: m
                   a) Number of Moles:
                     Number of moles = Given number of particles/Avogadro’s

                       Number

                n = N/ NA
                     Number of Moles= Given mass/Molar mass
                n= m/M

                   b) Mass:

                        Mass = No of moles X Molar mass
                m= n X M







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