And so we take the product...
I had to use Wolfram to find the atomic weight of Barium Chloride.
This tells me that 1 mole of
89.1 g is 0.428 of one mole (rounding)
1 mole is
Each molecule is 1 Barium and 2 chlorine, a total of 3 atoms, so multiply the number of molecules by 3 gives you