find the mr of ammonium hydroxide then find moles using moles=mass/mr then write out the balanced equation for ammonium hydroxide -> ammonium sulfate: 2 NH4OH + H2SO4 -> (NH4)2SO4 + 2 H20 because the ration is 2:1, divide the number of moles by 2 then find the mr of ammonium sulfate and find mass using the same equation