How many chloride ions are in a 220 grams of calcium chloride?

The Ions present in CaCl₂ are,

Ca²⁺ Cl⁻ Cl⁻

Means 1 formula unit contains 1 Ca²⁺ ion and 2 Cl⁻ ions.

Also, 1 mole of CaCl₂ contains 6.022 * 10²³ formula units.

So, 1 mole formula units of CaCl₂ contain,

2 * 6.022 * 10²³ = 1.20 * 10²⁴ Cl⁻ Ions

Now, Calculating number of moles contained by 220 g of CaCl₂,

As,

110.98 g of CaCl₂ = 1 mole

Then,

220 g of CaCl₂ = X moles

Solving for X,

X = (220 g * 1 mol) : 110.98 g

X = 1.98 moles

As,

1 mole contained = 1.20 * 10²⁴ Cl⁻ Ions

Then,

1.98 mole will contain = X Cl⁻ Ions

Solving for X,

X = (1.98 mol * 1.20 * 10²⁴ Ions) : 1mol

X = 2.38 * 10²⁴ Cl⁻ Ions