To determine the amount of Na2CO3 needed to precipitate all the copper ions in CuSO4, we need to use the stoichiometry of the balanced chemical equation between Na2CO3 and CuSO4.
The balanced chemical equation is:
Na2CO3 + CuSO4 -> CuCO3 + Na2SO4
From this equation, we can see that for every 1 mole of CuSO4, we need 1 mole of Na2CO3.
First, let's calculate the number of moles of CuSO4:
Moles of CuSO4 = Volume of CuSO4 solution (in L) x Concentration of CuSO4 (in mol/L)
= 26.7 mL x (1 L / 1000 mL) x 0.159 mol/L
= 0.00425 mol
Since the stoichiometry of the reaction is 1:1 between CuSO4 and Na2CO3, we need an equal number of moles of Na2CO3 to precipitate all the copper ions.
Therefore, we need 0.00425 mol of Na2CO3.
Now let's calculate the volume of 0.109 M Na2CO3 solution required to obtain 0.00425 mol of Na2CO3:
Volume of Na2CO3 solution (in L) = Moles of Na2CO3 / Concentration of Na2CO3 (in mol/L)
= 0.00425 mol / 0.109 mol/L
= 0.0390 L
Finally, let's convert the volume to mL:
Volume of Na2CO3 solution (in mL) = Volume of Na2CO3 solution (in L) x 1000 mL/L
= 0.0390 L x 1000 mL/L
= 39.0 mL
Therefore, you would need 39.0 mL of 0.109 M Na2CO3 to precipitate all the copper ions in 26.7 mL of 0.159 M CuSO4.