"Published in Newark, California, USA"
The aluminum in a 759.08 mg of impure ammonium aluminum sulfate sample was precipitated as Al(OH)3 and ignited at 1100°C to yield a precipitate of Al2O3 weighing 387.953 mg. Express the result of analysis in terms of % Al.
Solution:
From the description of a given problem, it is about gravimetric analysis because it involves the analysis of a certain element or a compound in a sample. Most of the sample is either impure or a mixture of two or more compounds. In this case, we will use the molecular weights as their factors to solve for the weight of a pure substance or a compound.
The weight of Al in Al2O3, we have
Therefore, the % Al in a sample is
