How many total moles of ions are released when each of the following samples dissolves completely in water?
(a) 0.734 mol of Na2HPO4 (b) 3.86 g of CuSO4·5H2O
(c) 8.66 × 1020 formula units of NiCl2
Solution 13P
Here we have to calculate how many total moles of ions are released when each of the following samples dissolves completely in water.
Step 1
(a) 0.734 mol of Na2HPO4
1st we will write a chemical equation for the dissociation of K3PO4.
Na2HPO4 (s) → 2 Na+ (aq) + HPO4 2 (aq)
From the above reaction it has been found that 3 moles of ions are released when one mole of Na2HPO4 dissolves,so the total number of moles released can be calculated as,
0.734 mol Na2HPO4 3 mol ions / mol Na2HPO4 = 1.47 mol of ions Na+ ions
0.734 moles of HPO42- is also present.
Thus total mole of ion = 1.47 + 0.734 = 2.202 mol
Thus 2.202 moles of ions are released when Na2HPO4 samples dissolves completely in water.
