The gas obtained by calcining 1 kg limestone was passed through a tube with hot coal. The resulting product

The gas obtained by calcining 1 kg limestone was passed through a tube with hot coal. The resulting product was treated with copper oxide. At the same time, copper with a mass of 864 g was obtained. Calculate the yield of the product of the second reaction from the theoretically possible, taking into account that the mass fraction of calcium carbonate in limestone is 90%. assuming the product yield of the sandy and the first reaction equal to 100%.

Given:
m (limestone) = 1 kg = 1000 g
ω (CaCO3) = 90%
m (Cu) = 864 g
η1 = η3 = 100%
Find: η2 -?
Decision:
1) CaCO3 = (tOC) => CaO + CO2 ↑;
CO2 + C = (tOC) => 2CO ↑;
CO + CuO = (tOC) => Cu + CO2 ↑;
2) m (CaCO3) = ω (CaCO3) * m (limestone) / 100% = 90% * 1000/100% = 900 g;
3) n (CaCO3) = m (CaCO3) / M (CaCO3) = 900/100 = 9 mol;
4) n (CO2) = n (CaCO3) = 9 mol;
5) n theory. (CO) = n (CO2) * 2 = 9 * 2 = 18 mol;
7) n (Cu) = m (Cu) / M (Cu) = 864/64 = 13.5 mol;
8) n practical (CO) = n (Cu) = 13.5 mol;
10) η2 = η (CO) = n practical. (CO) * 100% / n theory. (CO) = 13.5 * 100% / 18 = 75%.
Answer: The CO product yield is 75%.