Question

Sodium sulfate dissolves as follows: Na2SO4(s) → 2Na (aq) SO42- (aq). How many moles of Na2SO4 are required to make 1.0 L of solution in which the Na concentration is 0.10 M

Answer 1

Answer:

0.05 moles of sodium sulfate are required.

Explanation:

$Na_2SO_4(s) \rightarrow 2Na^+ (aq) SO_4^{2-} (aq)$

Concentration of sodium ions in 1 L = 0.10 M

$0.10 M=\frac{\text{Moles of sodium ions}}{1.0 L}$

Moles of sodium ions = 0.10 mol

1 mole of sodium  sulfate gives 2 moles of sodium ions.

Then 0.10 mol of sodium ions will be given by:

$\frac{1}{2}\times 0.10 mol=0.05 mol$

0.05 moles of sodium sulfate are required.