Question

 A 1.000 g sample of an aluminum is dissolved and the sulfate precipitated as BaSO4. The precipitate weighed 

0.3486 g after it was washed and ignited. Assuming all the sulfate and aluminum in the sample were in the form 

of K2Al2(SO4)3 • 24 H2O, calculate the percentage of Al2O3 in the sample.

Answer 1

Moles of aluminiun$=\frac{1.000}{26.981539}= 0.037 moles$

Moles of $BaSO_4=$ $\frac{0.3486}{233.38 }=1.49×10^{-3}moles$