question_answer 61)

  Compute the difference in masses of 103 moles each of magnesium atoms and magnesium ions.     (Mass of an electron )

Answer:

  103 moles of Mg atoms =103 x 6.022 x 1023  atoms 103 moles of  ions = 103 x 6.022 x 1023 ions One ion is formed from one Mg atom by loss of 2 electrons, As i.e., difference in the mass of 1 Mg atom and 1  ion = mass of 2 electrons Difference in the mass of 6.022 x 1026 Mg atoms and  ions = mass of 2 x 6.022 x 1026 electrons = 2 x 6.022 x 1026 x 9.1 x  kg. (as mass of an electron = 9.1 x  kg) = 109.6004 x 10-5 kg = 1.096 xkg = 1.096 g