Dry air at sea level contains $75.5\%\, N_2$ by mass. If the total atmospheric pressure is $1 \,atm$,the partial pressure of nitrogen is approximately $... \,atm$.

$A$ gas is filled in a cylinder. If its temperature is increased by $20\%$ and its volume decreases by $10\%$, what percentage of the gas will have leaked out?

When the volume of a system is increased two times and the temperature is decreased to half of its initial temperature,then the pressure becomes ...... times.

Two identical glass bulbs are interconnected by a thin glass tube. Initially,both bulbs are at $0^{\circ}C$. $A$ gas is filled in these bulbs. When one bulb is placed in ice $(0^{\circ}C)$ and the other bulb is placed in a hot bath,the pressure of the gas becomes $1.5$ times the initial pressure. The temperature of the hot bath will be ...... $^{\circ}C$.

At a constant temperature,by what percentage $(\%)$ must the pressure of a given mass of gas be increased so that its volume decreases by $10\%$ (in $.1$)?

$A$ pressure cooker contains air at $1$ atm and $30^\circ C$. If the safety valve of the cooker blows when the inside pressure $\ge 3$ atm,then the maximum temperature of the air inside the cooker can be .... $^\circ C$.