According to Charles's Law,what is the slope of the graph of volume versus temperature? ($V_0$ is the volume of the gas at $0\,^{\circ}C$ and $V_t$ is the volume of the gas at $t\,^{\circ}C$)

The equation for Boyle's law is:

The volume and pressure of a balloon filled with hydrogen gas are $1 \ bar$ and $175 \ dm^{3}$. When the balloon reaches a certain height,its pressure decreases to $0.8 \ bar$. Calculate the new volume of the balloon. (in $dm^{3}$)

If the volume of $N_2$ gas at $STP$ is $204.75 \, mL$,then calculate the volume of the gas at $1.5 \, bar$ pressure and $127 \, ^oC$ temperature.

In the equation $PV = nRT$,which one cannot be the numerical value of $R$?

If two identical containers $X$ and $Y$ containing $O_2$ gas are subjected to expansion from volume $V$ to $2V$ under identical isothermal conditions by applying pressure changes of $\Delta P$ and $0.2 \Delta P$ respectively,then the ratio of the mass of $O_2$ gas in container $X$ to container $Y$ is