In: Chemistry
A 0.8027 g sample of impure al2(CO3)3 decomposed with HCL: the
liberated CO2 was collected on calcium oxide and found to weight
0.0507g calculate the percentage of aluminum in the sample
The balanced equation for the given reaction is -
Al2(CO3)3 (aq) + 6 HCl (aq) ----------> 2AlCl3 (aq) + 3CO2 (g) + 3 H2O (l)
Mass of CO2 produced = 0.0507 g
Therefore - Number of mols of Al2(CO3)3 must present to evolve this much of CO2 is
= (0.0507 g)(1 mol CO2/44 g/mol)(1 mol Al2(CO3)3 /3 mol CO2)
= 3.84*10-4 mol Al2(CO3)3
Therefore, the number of mols of Al2(CO3)3 in the impure sample
= [3.84*10-4 mol Al2(CO3)3]* (2 mol Al / Al2(CO3)3)
= 7.68*10-4 mol Al
Therefore - Mass of Al in the impure sample = (7.68*10-4 mol Al)(27 g / 1 mol Al)
= 0.02074 g
Therefore, % weight of Al in imure sample = (0.02074 g/0.8027 g)*100 = 2.60 %