How many grams of must be dissolved in $0\mathrm{.}500L$ of $0\mathrm{.}35MN{H}_3$ to produce $(N{H}_4{)}_{2}S{O}_4$ a solution with $pH=9?($Assume that the solution volume remains at $0\mathrm{.}500L.)$

$K_w=[H_3{O}^{+}][O{H}^{-}]=1\mathrm{.}0{10}^{-14}$

$-N{H}_3^{-}+H_2^{-}ON{H}_4^{-}\frac{+}{b}ar(OH{)}^{-},1\mathrm{.}8{10}^{-5}=K_b$