An excess of copper (II) chloride solution was added to 106 g of a solution with a mass fraction of potassium
An excess of copper (II) chloride solution was added to 106 g of a solution with a mass fraction of potassium phosphate of 4%. Determine the mass of the precipitated sediment.
1. Let us write the equation for the reaction of solutions of copper chloride (2) with potassium phosphate:
3CuCl2 + 2K3PO4 = Cu3 (PO4) 2 ↓ + 6KCl;
2.Calculate the mass of potassium phosphate:
m (K3PO4) = w (K3PO4) * m (solution) = 0.04 * 106 = 4.24 g;
3.Calculate the chemical amount of potassium phosphate:
n (K3PO4) = m (K3PO4): M (K3PO4);
M (K3PO4) = 3 * 39 + 31 + 4 * 16 = 212 g / mol;
n (K3PO4) = 4.24: 212 = 0.02 mol;
4.determine the amount of sediment:
n (Cu3 (PO4) 2) = n (K3PO4): 2 = 0.02: 2 = 0.01 mol;
5. find the mass of copper phosphate:
m (Cu3 (PO4) 2) = n (Cu3 (PO4) 2) * M (Cu3 (PO4) 2);
M (Cu3 (PO4) 2) = 3 * 64 + 2 * 31 + 8 * 16 = 382 g / mol;
m (Cu3 (PO4) 2) = 0.01 * 382 = 3.82 g.
Answer: 3.82 g.