Calculate the mass of the formed silicic acid as a result of the interaction of sodium silicate with 100 g. 20% hydrochloric acid solution.
m (solution HCl) = 100 g
w% (HCl) = 20%
m (H2SiO3) -?
2HCl + Na2SiO3 = 2NaCl + H2SiO3, – we solve the problem, relying on the composed reaction equation:
1) Find the mass of hydrochloric acid in the reacted solution:
m (HCl) = 100 g * 0.2 = 20 g
2) Find the amount of hydrochloric acid:
n (HCl) = m: M = 20 g: 36.5 g / mol = 0.55 mol
3) We compose a logical expression:
If 2 mol of HCl gives 1 mol of H2SiO3,
then 0.55 mol HCl will give x mol H2SiO3,
then x = 0.275 mol.
4) Find the mass of silicic acid precipitated during the reaction:
m (H2SiO3) = n * M = 0.275 mol * 78 g / mol = 21.45 g.
Answer: m (H2SiO3) = 21.45 g.
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