Which gas has a density of $1.24 \ g/L$ at $0^{\circ} C$ and $1 \ atm$ pressure?

$A$ rigid nitrogen tank stored inside a laboratory has a pressure of $30 \ atm$ at $06:00 \ am$ when the temperature is $27^{\circ} C$. At $03:00 \ pm$, when the temperature is $45^{\circ} C$, the pressure in the tank will be $...... \ atm.$ [nearest integer]

At $25 \, ^oC$ and $730 \, mm$ pressure,$380 \, mL$ of dry oxygen gas is collected. If the temperature is kept constant,what will be the volume of oxygen gas at $760 \, mm$ pressure (in $, mL$)?

An $LPG$ (Liquefied Petroleum Gas) cylinder weighs $15.0 \ kg$ when empty. When full, it weighs $30.0 \ kg$ and shows a pressure of $3.0 \ atm$. In the course of usage at $27^{\circ}C$, the mass of the full cylinder is reduced to $24.2 \ kg$. The volume of the used gas in cubic metre at the normal usage condition ($1 \ atm$ and $27^{\circ}C$) is (assume $LPG$ to be normal butane and it behaves ideally). (in $m^3$)

The temperature at which real gases obey the ideal gas laws over a wide range of pressure is called:

What will be the pressure exerted by a mixture of $3.2 \ g$ of methane and $4.4 \ g$ of carbon dioxide contained in a $9 \ dm^3$ flask at $27^{\circ} C$?