Which of the following laws gives the relation between volume and temperature?

If $1 \, L$ flask contains $O_2$ at a pressure of $7.6 \times 10^{-10} \, mm \, Hg$ at $0 \, ^\circ C$,then the number of $O_2$ molecules will be ......

Which of the following equations represents the ideal gas equation?

The density of oxygen gas at $5 \text{ atm}$ and $127^{\circ} C$ will be (in $\text{ g/L}$)

$N_2$ is found in a $1 \ L$ flask under $100 \ kPa$ pressure and $O_2$ is found in another $3 \ L$ flask under $320 \ kPa$ pressure. If the two flasks are connected,the resultant pressure is $............... \ kPa$.

$A$ certain sample of gas has a volume of $0.2 \ L$ measured at $1 \ atm$ pressure and $0 \ ^oC$. At the same pressure but at $273 \ ^oC$,its volume will be ................ $L$.