# A 82.7 g sample of dinitrogen monoxide is confined in a 2.0 L vessel, what is the pressure (in atm) at 115°C?

$P = \frac{n R T}{V}$; we assume (reasonably?) ideal gas behaviour for ${N}_{2} O$.
The only challenge to this problem is selecting the appropriate gas constant; here, we choose $R = 0.0821 \cdot L \cdot a t m \cdot {K}^{- 1} \cdot m o {l}^{- 1}$. This gas constant (and others) would be supplied. Of course, we've got to choose the right one for the job!
So, P = ((82.7*g)/(44.01*g*mol^-1)xx0.0821*L*atm*K^(-1)*mol^-1xx388K)/(2.0*L) = ?? atm