What is the value of $1 \, bar$ in Pascals? What does this value represent?

$A$ vessel of volume $V \ L$ contains an ideal gas at $T \ K$. The vessel is partitioned into two equal parts. The volume (in $L$) and temperature (in $K$) in each part is respectively

Fill in the blanks:
$(1)$ The properties of gases were first measured by ......... .
$(2)$ The dipole-dipole interaction energy between stationary polar molecules is proportional to .......... .
$(3)$ The interaction energy between rotating polar molecules is proportional to .......... .
$(4)$ The bond energy of a hydrogen bond is about ......... $kJ \ mol^{-1}$.

At a constant temperature and pressure,the ratio of the densities of two gases is $1 : 16$. The ratio of their rates of diffusion will be ........

Explain the following terms:
$(i)$ Isotherm
$(ii)$ Isochore
$(iii)$ Isobar

$CO_2$ and $N_2$ do not support combustion. However,$CO_2$ is preferred over $N_2$ for extinguishing fires because $CO_2$ .......