5. A solution is prepared by dissolving 10.8 g ammonium sulfate in enough water to make 100.0 mL of stock solution. A 10.00 mL sample of this stock solution is added to 50.00 mL of water. Calculate the concentration of ammonium ions in the final solution. (A) 0.136 M (B) 0.272 M (C) 0.818 M (D) 0.163 M (E) 0.327 M