Write the expression for the equilibrium constant Kp for the following reaction. Enclose pressures in parentheses and do NOT write the chemical formula as a subscript. For example, enter (PNH3)^2 as (PNH3)^2. If either the numerator or denominator is 1, please enter 1.
NH4HSe(s) ↔ NH3(g) + H2Se(g)