Question

Please help How many moles of Pb(NO3)2 are required if 12 moles of Al(NO3)3 are produced

Answer 1

Answer is: 18 moles of lead(II)-nitrate.

Balanced chemical reaction: 
3Pb(NO₃)₂ + 2AlCl₃ → 2Al(NO₃)₃ + 3PbCl₂.
n(Al(NO₃)₃) = 12 mol.
From chemical reaction: nAl(NO₃)₃) : n(Pb(NO₃)₂) = 2 : 3.
n(Pb(NO₃)₂) = 3 · 12 mol ÷ 2.
n(Pb(NO₃)₂) = 18 mol; amount of substance.
Al(NO₃)₃ is aluminium nitrate.
AlCl₃ is aluminium chloride.