The mole concept

The mole concept n A mole of Oxygen gas O2 has a mass of 32g then 320g will be 10moles of O2 This because :  320g O2 x 1mol O2 / 32g O2  =  10moles O2 Then moles n = mass of the substance ( g) / molar mass of the substance (g/mol)                       For the above example                        n O2 = 320g O2 / 32g O2  = 10 moles O2   In the same way ... the mass of  5 moles of O2 will be equal to :     n x molar mass (g/mol) O2                                                                                                                      5mol O2 x 32g/mol  O2                                                                                                                      160g O2  

Moles of substance n                          =  g of substance / molar mass of susbtance (g/mol) Mass of substance (g)                         =  Moles of substance n x molar mass of substance (g/mol) Molar mass of substance (g/mol)     = Mass of substance (g) / moles of substance n