How many calcium ions are there in 12.6g of calcium Carbonate?
12.6-g CaCO₃ = (12.6-g/100-g/mol) = 0.126-mole CaCO₃
0.126-mol CaCO₃ => 0.126-mol Ca⁺² + 0.126-mol CO₃²⁻
No. Ca⁺² ions = (0.126-mol Ca⁺² ions) x (6.02 x 10²³ Ca⁺² ions/ mol Ca⁺² ions) = 7.59 x 10²² Ca⁺² ions in 12.6-g CaCO₃