Gold can be recovered from sea water by re- acting the water with zinc, which is refined from zinc oxide.

Question

2 ZnO(s) + C(s) −→ 2 Zn(s) + CO2(g) 2 Au3+(aq) + 3 Zn(s) −→3 Zn2+(aq) + 2 Au(s) The zinc displaces the gold in the water. What mass of gold can be recovered if 9.7 g of ZnO and an excess of sea water are available?
Answer in units of g

Answer 1

mols ZnO = grams ZnO/molar mass ZnO
Using the coefficients in the balanced equation, convert mols ZnO to mols Au.
Now convert mols Au to grams. g = mols x atomic mass.