Answer:
[tex]\boxed{ \text{9.0 mol of ZnCO$_{3}$}}[/tex]
Explanation:
(a) Balanced equation
3ZnCO₃ + 2H₃PO₄ ⟶ Zn₃(PO₄)₂ + 3H₂O + 3CO₂
(b). Calculation
You want to convert moles of Zn₃(PO₄)₂ to moles of ZnCO₃
The molar ratio is 1 mol Zn₃(PO₄)₂:3 mol ZnCO₃
[tex]\text{Moles of ZnCO$_{3}$} =\text{3.0 mol Zn$_{3}$(PO$_{4})_{2}$ } \times \dfrac{\text{3.0 mol ZnCO$_{3}$}}{\text{1 mol Zn$_{3}$(PO$_{4}$)$_{2}$}} \\\\\\= \text{9.0 mol ZnCO$_{3}$}[/tex]
You need [tex]\boxed{ \textbf{9.0 mol of ZnCO$_{3}$}}[/tex] to form 3.0 mol of Zn₃(PO₄)₂.