For an ideal gas:
\[
PV=nRT.
\]
Density form of ideal gas equation is:
\[
\rho=\frac{PM}{RT}.
\]
For carbon dioxide:
\[
M=44\text{ kg/kmol}.
\]
Temperature:
\[
T=263^\circ C=263+273=536\text{ K}.
\]
Pressure:
\[
P=2\text{ atm}.
\]
Using:
\[
1\text{ atm}=101.325\text{ kPa},
\]
we get:
\[
P=202.65\text{ kPa}.
\]
Use:
\[
R=8.314\ \text{kPa}\cdot\text{m}^3/(\text{kmol}\cdot\text{K}).
\]
Now:
\[
\rho=\frac{202.65\times44}{8.314\times536}.
\]
Calculate numerator:
\[
202.65\times44=8916.6.
\]
Calculate denominator:
\[
8.314\times536=4456.3.
\]
Therefore:
\[
\rho=\frac{8916.6}{4456.3}.
\]
\[
\rho\approx2\text{ kg/m}^3.
\]
Hence, the density of carbon dioxide is:
\[
2\text{ kg/m}^3.
\]