# How many moles of ammonia are there in a 5.00 L cylinder if they exert a pressure of 8.65 atm at 18.0 Celsius?

$P V = n R T$
with $R = 0.08214 \frac{L \cdot a t m}{m o l \cdot K}$
With 318°C=273+18=291 K
$n = \frac{P V}{R T} + \frac{5 \cdot 8.65}{291 \cdot 0.08214} = 1.81 m o l$