Answer
$d=1.25\frac{g}{L}$
Work Step by Step
We know that
$PV=nRT$
But $n=\frac{m}{M}$ Where $m$ and$M$ are mass in grams and molar mass respectively
$\implies PV=\frac{mRT}{M}$
This can be rearranged as
$PM=\frac{m}{V}RT$
But $d=\frac{m}{V}$ where $d$ represents density
$\implies PM=dRT$
This can be rearranged as
$d=\frac{PM}{RT}$
We plug in the known values to obtain:
$d=\frac{1.00\times 28.0134}{0.08206\times 273.15}=1.25\frac{g}{L}$
