Answer
$2.14\frac{g}{L}$
Work Step by Step
From ideal gas law
$n=\frac{PV}{RT}$
We plug in the known values to obtain:
$n=\frac{0.897\times 1}{0.08206\times 297}=0.036804mol$
Now $0.036804mol\times \frac{58.12g}{1mol}=2.14g$
Thus the density of ammonia is $2.14\frac{g}{L}$