Question

a student has 10.0 ml of a phosphate solution that contains .124 moles per litre of phosphate. a student reacts this with excess ammonium and magnesium ions under slightly basic conditions. under the reaction pH conditions, the phosphate becomes HPO4 and reacts with NH4, Mg and water to produce.3005g of struvite. calculate percent yield.

Answer 1

1 mole of phosphate (PO₄^2-) = 94.97 gm

0.124 moles of phosphate (PO₄^2-) = (94.97 x 0.124) gm = 11.776 gm

Struvite = Magnesium Ammonium Phosphate Hexahydrate (NH₄MgPO₄.6H₂O)

Molar Mass of Struvite = 245.4065 g/mol

So, 1 mole of Struvite = 245.4065 g

0.124 moles of Struvite = (245.4065 x 0.124) g = 30.43 g

Now yield calculation:

100% yeld is 0.124 moles of phosphate will give 0.124 moles of struvite

0.124 moles of phosphate will give 30.43 g of struvite.

struvite got = 0.3005 gm

% Yield = (0.3005/30.43) x 100 = 0.98 %