185 g of technical calcium hydroxide, which contains 80% calcium hydroxide, reacts with ammonium

| September 20, 2021 | education

185 g of technical calcium hydroxide, which contains 80% calcium hydroxide, reacts with ammonium chloride. What is the mass of the resulting ammonia?

Given:
m tech. (Ca (OH) 2) = 185 g
ω (Ca (OH) 2) = 80%

Find:
m (NH3) -?

Solution:
1) Ca (OH) 2 + 2NH4Cl => CaCl2 + 2NH3 + 2H2O;
2) M (Ca (OH) 2) = Mr (Ca (OH) 2) = Ar (Ca) * N (Ca) + Ar (O) * N (O) + Ar (H) * N (H) = 40 * 1 + 16 * 2 + 1 * 2 = 74 g / mol;
M (NH3) = Mr (NH3) = Ar (N) * N (N) + Ar (H) * N (H) = 14 * 1 + 1 * 3 = 17 g / mol;
3) m (Ca (OH) 2) = ω (Ca (OH) 2) * m tech. (Ca (OH) 2) / 100% = 80% * 185/100% = 148 g;
4) n (Ca (OH) 2) = m (Ca (OH) 2) / M (Ca (OH) 2) = 148/74 = 2 mol;
5) n (NH3) = n (Ca (OH) 2) / 2 = 2/2 = 1 mol;
6) m (NH3) = n (NH3) * M (NH3) = 1 * 17 = 17 g.

Answer: The NH3 mass is 17 g.



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