magnesium nitrate decompses in water and releases ammonia gas. If 355ml of ammonia is produced at STP, whit is the mass of Magnesim nitrate that reacted. Equation is Mg3N2+6H2O=3Mg(OH)2+2NH3

1 answer

You mean magnesium NITRIDE. Magnesium nitrate is Mg(NO3)2 and it does not produce NH3 when reacted with H2O.
Convert 355 mL NH3 to moles. moles = L/22.4 = ? moles NH3.
Convert moles NH3 to moles Mg3N2 using the coefficients in the balanced equation.
?moles NH3 x (1 mole Mg3N2/2 moles NH3) = ? moles Mg3N2.
Convert to grams. g = moles x molar mass.