Question

500 mole of ammonia (nh3) occupies a 1.2 l flask at 150°c. calculate the pressure of the ammonia inside the flask.

Answer 1

Given; 
no. of moles (n) = 500 moles
volume (V) = 1.2 l
temperature (T) = 150°C = (150 + 273 )k = 423 k
gas constant (R) = 0.0821 L- atm / mole-K

then,

PV = nRT
P × 1.2 = 500 × 0.0821 × 423
P =  14,470.125 atm

But I guess pressure is too high. Well this should be the way.