✔ 最佳答案
7.
In the Hall-Heroult process, anhydrous aluminium oxide is reduced toaluminium according to the chemical equation:
2Al2O3(s) → 4Al(l) + 3O2 (g)
Calculate the mass of aluminium oxide reacted if 385g of Al was produced andthe percent yield was found to be 89.3%.
No. of moles of Al formed = 385/27 = 14.26 mol
For 100% yield, no. of moles of Al2O3 needed = 14.26 x(1/2) = 7.13 mol
For 100% yield, mass of Al2O3 needed = 7.13 x (27x2 +16x3) = 727.3 g
For 89.3% yield, mass of Al2O3 needed = 727.3/89.3% = 814.4 g
8)
Calculate the number of moles of H2O formed when 0.200 mole of Ba(OH)2is treated with 0.500 mol of HClO3 according to the chemicalreaction shown below.
Ba(OH)2 + 2HClO3 → Ba(ClO3)2 + 2H2O
When Ba(OH)2 is completely reacted,
no. of moles HClO3 needed = 0.200 x 2 = 0.400 mol
Hence, HClO3 is in excess, and Ba(OH)2 is completelyreacted.
No. of moles of Ba(OH)2 reacted = 0.200 mol
No. of moles of water formed = 0.200 x 2 = 0.400 mol
