In 1 mole of
, there are 3 moles of ions, 1 mole of Ca^{2+} and 2 mole of
.

Molar mass of
is 110.98 g/mol. Calculating number of moles from given mass as follows:

Thus, number of moles of ions will be
.
Since, 1 mole of any substance has
units of that substance where
is Avogadro's number.
Thus, 9.38 mol of ions will have
number of ions.
Therefore, total number of ions in 347 g of
is
.