Answer
$4.12\frac{g}{L}$
Work Step by Step
From ideal gas law
$n=\frac{PV}{RT}$
We plug in the known values to obtain:
$n=\frac{\frac{797}{760}\times 1}{0.08206\times 371}=0.034446mol$
Now $0.034446mol\times \frac{119.5g}{1mol}=4.12g$
Thus the density of ammonia is $4.12\frac{g}{L}$
