Question

The difference in the mass of 100 moles each of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron.

Answer 1

A sodium atom and ion, differ by one electron. For 100 moles each of sodium atoms and ions there would be a difference of 100 moles of electrons. 

Mass of 100 moles of electrons= 5.48002 g 

Mass of 1 mole of electron = 5.48002 / 100 g 

Mass of one electron =  5.48002 /100 × 6.022 ×10²³   = 9.1 ×10^-28g 

                                                                                     =  9.1×10^-31 kg