In a 1.0 M solution of CaCl2, how many moles of calcium ions and how many moles of chloride ions are in 1 dm3?

Question

of this solution? how many formula units are in 1.0 dm3?

Answer 1

1 dm3 = 1 liter.

So a 1 molar solution has one mole of CaCl2

Now break that up into ions and you'll see how many moles of chloride ions you have. (hint: 2 atoms of Cl in one molecule of CaCl2)

Answer 2

1 molecule of CaCl2 has 1 Ca ion and 2 Cl ions. 1.0M solution is 1 mole of CaCl2 in 1 dm3. Therefore, in 1 dm3, 1 mole of CaCl2 contains 1 mole of Ca ions and 2 moles of Cl ions.