Cu^2+(aq) + 4NH3 (aq)---> [Cu(NH3)4]^2+ (aq)This time, ammonia is a limiting agent, so finding the total amount of NH3 has reacted, so that you can find the amount of tetraaminecopper(II) ions formed.Then, one tetraaminecopper(II) ions will bind with one sulphate ion and one water molecule, then you can get it.Can you explain that a little more?