so first write the equation: PbSO4 + 2Zn ----> 2ZnSO4 + Pb if we have 0.507 moles of zinc and the lead sulfate isnt limiting then we just go between ratios 2:2 so its a 1:1 ratio
so all that needs to be done is to find the mass of ZnSO4 using an equation mass = moles x RFM mass of ZnSO4 = 0.507 x 161.45 mass of ZnSO4 = 81.85g hope that helps