Question

how many moles and numbers of ions each type,are present Iin the following aqueous solution? 51.5 ml of 1.55 M magnesium chlorides

Answer 1

molarity = moles / vol in litres

So moles = molarity * vol in litres

               = 1.55 * 51.5 /1000 = .079825

MgCl2 >   Mg+2   + 2 Cl-

   (aq)       (aq)          (aq)

1                 1          2       mole ratio

.079825      .079825    0.15965    moles  

So it contains   Mg+2 ions = 0.078925 moles = 0.078925* 6.023*10^23 Mg +2 ions   = .4754*10^23 ions

                        Cl-   ions = 0.15965 mole      =   0.15965* 6.023 * 10*23 = 0.9616 * 10*23 ions