How many moles of sodium ions, Na⁺, are present in 5.63 grams of sodium sulfate, Na₂SO₄?

Question

Quizplus · Accepted Answer

1 mole of Na2SO4 contains 2 moles of Na+ ions and 1 mole of SO42- ions. 
Therefore, the number of moles of Na+ ions in 5.63 grams of Na2SO4 can be calculated as follows:

Molar mass of Na2SO4 = 2(22.99 g/mol) + 1(32.06 g/mol) + 4(16.00 g/mol) = 142.04 g/mol

Number of moles of Na2SO4 = 5.63 g / 142.04 g/mol = 0.0396 moles

Number of moles of Na+ ions = 2 × 0.0396 moles = 0.0792 moles

Since each mole of Na2SO4 contains 1 mole of Na2S ions, which in turn contain 1 mole of Na+ and 1 mole of S2- ions, the answer can also be expressed in terms of NaS ions. 
1 mole of Na2S is equivalent to 2 moles of NaS ions. 
Therefore, the number of moles of NaS ions in 5.63 grams of Na2SO4 is equal to:

0.0396 moles of NaS ions = 0.0396 moles of Na2S ions × (2 moles of NaS ions /1 mole of Na2S ions) = 0.0792 moles of NaS ions.

Thus, the answer is 7.92×102 - 2S0 ions of NaS.

How Many Moles of Sodium Ions, Na+, Are Present in 5.63

How Many Moles of Sodium Ions, Na⁺, Are Present in 5.63