A solution of orthophosphoric acid weighing 49 kg with a mass fraction of H3PO4 50% neutralized calcium hydroxides.

| December 29, 2020 | education

A solution of orthophosphoric acid weighing 49 kg with a mass fraction of H3PO4 50% neutralized calcium hydroxides. Determine the mass of calcium phosphate formed.

1.Let’s find the mass of the substance (H3PO4) by the formula:
W = m (substance): m (solution) × 100%,
hence m (substance) = (m (solution) × w): 100%.
m (substance) = (49k g × 50%): 100% = 24.50 g.
2. Let’s find the amount of phosphoric acid substance.
n = m: M.
M ((H3PO4) = 3 + 31 + 64 = 98 g / mol.
n = 24.5 g: 98 g / mol = 0.25 mol.
3. Let’s compose the equation of the reaction between phosphoric acid and calcium hydroxide.
2H3PO4 +3 Ca (OH) 2 = Ca3 (PO4) 2 + 6H2O.
For 2 mol of phosphoric acid there is 1 mol of calcium phosphate.
The substances are in quantitative ratios of 2: 1. The amount of acid substance will be 2 times more than the amount of calcium phosphate substance.
n (Ca3 (PO4) 2) = 0.25: 2 = 0.125 mol.
4.Let’s find the mass of calcium phosphate by the formula:
m = n × M,
M (Ca3 (PO4) 2) = 40 × 3 + 2 (31 + 16 × 4) = 120 + 2 × 95 = 310 g / mol.
m = 310 g / mol × 0.125 mol = 38.75 g.
Answer: 38, 75



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.