Hi there!
Sodium Sulfate (Na₂SO₄) when dissolved in water, follows the following dissociation reaction:
Na₂SO₄(s) ⇄ 2Na⁺ (aq) + (SO₄)⁻² (aq)
So, if you have n molecules of sodium sulfate in water, you will observe 2 times this amount of sodium ions in solution. In this case, you have 22 molecules of sodium sulfate, so you will observe 44 sodium ions in solution.