Ammonium nitrate, a common agricultural fertilizer, is used as an explosive in fireworks. It was the material

Ammonium nitrate, a common agricultural fertilizer, is used as an explosive in fireworks. It was the material used in the devastation and tragic explosion of an Oklahoma City federal building in 1995. How many liters of gas, at 341.4 °C and 1.057 atm, are formed by the explosive decomposition of 16.3 kg ammonium nitrate which forms nitrogen gas, oxygen gas and water vapor?

Please help me out I'm having a lot of trouble

2 NH4NO3 → 2 N2(g) + O2(g) + 4 H2O(g)
The essence of this equation is that every 2 moles of NH4NO3 produce 2 + 1 + 4 = 7 moles of various kinds of gases.

(16.3 kg NH4NO3) x (1000 g/kg) / (80.0435 g NH4NO3/mol) x (7/2) x (22.4 L/mol) x ((341.4 + 273.15) / 273.15) x (1.000 / 1.057) = 3.40 x 10^4 L gases