16,1 grams crystallized sodium sulphate ( the amount of water molecules are 10) is solved in water and diluted to 1,0 liter in a volumetric flask.
Explain the answer please
2007-04-22 02:47:49 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
The formula is Na2SO4 . 10 H2O, which would have a molecular weight of 322. 16.1 grams is 0.05 moles of the sulfate salt, but you get 2 moles of sodium due to the formula, so there are 0.10 moles of sodium. Dissolving it in 1 L, you would get a 0.10 M solution of Na+.
2007-04-22 02:56:43 · answer #1 · answered by TheOnlyBeldin 7 · 0⤊ 0⤋
the formula for the Na2SO4 with 10 moles water is, Na2SO4.10H2O. So to start the calculation, you have to find the molar mass of this compound. (23X2 for Na+32 for S+ 4X16 for O + 10(2X1 for H + 16 for O) = 322g/mol
Then you divide the mass of compound by the molar mass.
16.1g/322g/mol = 0.05mols of Na2SO4.10H2O.
Since 1litre of water is used, the concentration of Na2SO4 will be 0.05mol/litre. But since we need to find the concentration of Na+ in solution, we have to multiply the concentration by 2 because each Na2SO4 will contribute 2 Na+'s to the solution. Therefore, the concentration is,
o.05mol/litre X 2 = 0.1mol/litre
2007-04-22 10:31:32 · answer #2 · answered by boonu 2 · 0⤊ 0⤋