18/6Q

1- A 0.3516-g sample of a commercial phosphate detergent was ignitedat a red heat to destroy the organic matter. The residue was thentaken up in hot HCl, which converted the P to H3PO4. The phosphate was precipitated as MgNH4PO46H2O by addition of Mg2+ followed by aqueous NH3. After being filtered and washed, the precipitate was converted to Mg2P2O7 (222.57 g/mol) by ignition at 1000C. This residue weighted 0.2161 g.Calculate the percent P (30.974 g/mol) in the sample.

2- A graduated cylinder was filled to 25.0mL with a liquid.  A solid object weghing 73.5 grams was immeresed in liquid, raising the liquid level to 43.9mL.  Calculate the density of the solid object.