What is Avogadro number? Write its value.

Absolute zero $(0\, K)$ is that temperature at which

$10 \ g$ of a gas at $STP$ occupies a volume of $2 \ L$. At what temperature will the volume be doubled,if pressure and amount of the gas remain constant?

$A$ cylinder of volume $30 \, L$ contains oxygen at an initial gauge pressure of $15 \, atm$ and a temperature of $27^{\circ}C$. After some oxygen is withdrawn from the cylinder,the gauge pressure drops to $11 \, atm$ and its temperature drops to $17^{\circ}C$. The mass of oxygen taken out of the cylinder is approximately ........ $kg$. (Given: $R = 8.31 \, J \, mol^{-1} K^{-1}$,molar mass of $O_2 = 32 \, g/mol$ or $32 \times 10^{-3} \, kg/mol$)

What is molar mass?

$A$ cylindrical tube of cross-sectional area $A$ has two airtight,frictionless pistons at its two ends. The pistons are tied with a straight piece of metallic wire. The tube contains a gas at atmospheric pressure $P_0$ and temperature $T_0$. If the temperature of the gas is doubled,then the tension in the wire is: