Page 2 - 3.Lesson Notes_Pure and Impure Substances
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Difference between pure and impure substances


               Pure substances                              Impure substances or mixtures:
                   •  They are composed of same kind            •  They are composed of different
                       of particles                                 kind of particles



                   •  They are homogeneous                      •  They may be homogeneous or

                                                                    heterogeneous


                   •  They cannot be separated into             •  They can be separated into any

                       any other kinds of matter by                 other kinds of matter by physical
                       physical processes.                          processes.



                   •  They have fixed composition               •  They do not have fixed
                       throughout.                                  composition throughout.



                   •  They have fixed properties                •  They do not have fixed properties

                       throughout.                                  throughout.


                   •  They have fixed melting and               •  They do not have fixed melting

                       boiling points                               and boiling points


                   •  Examples: Elements and                    •  Examples: Mixtures

                       compounds
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