Question

A target mass of 20.415 g of zinc phosphate is desired. Calculate the moles of potassium phosphate required to meet the target mass of zinc phosphate. The molar mass of zinc phosphate is 386.11 g/mol. 

Answer 1

zinc nitrate can react with potassium phosphate to form insoluble compound, zinc phosphate. The balanced chemical equation can be written as shown;

$3Zn(NO_3)_2+2K_3PO_4 \to Zn_3(PO_4)_2+6KNO_3$

no. of moles of zinc phosphate$=20.415/386.11$

from the equation, no. of moles of$K_3PO_4=\frac{20.415}{386.11}\times 2=0.1057$