Calculate the mass of the salt that forms when phosphoric acid reacts with 4 g
July 29, 2021 | education|
Calculate the mass of the salt that forms when phosphoric acid reacts with 4 g of potassium containing 2.5% impurities. How much hydrogen is produced in this case?
1. The interaction of phosphoric acid with potassium proceeds according to the reaction equation:
2H3PO4 + 6K = 2K3PO4 + 3H2 ↑;
2.determine the mass of pure potassium:
m (K) = (1 – w (impurities)) * m (sample) = 0.975 * 4 = 3.9 g;
3.Calculate the chemical amount of potassium:
n (K) = m (K): M (K) = 3.9: 39 = 0.1 mol;
4.determine the amount of potassium phosphate formed:
n (K3PO4) = n (K): 3 = 0.1: 3 = 0.0333 mol;
5.Calculate the mass of potassium phosphate:
m (K3PO4) = n (K3PO4) * M (K3PO4);
M (K3PO4) = 39 * 3 + 31 + 4 * 16 = 212 g / mol;
m (K3PO4) = 0.0333 * 212 = 7.06 g.
Answer: 7.06 g.
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