What will be the effect on the density of $0.09 \ mol$ of a gas at $300 \ K$ if its pressure is increased?

Find the temperature in degree Celsius if volume and pressure of $2 \ mol$ ideal gas is $20 \ dm^3$ and $4.926 \ atm$ respectively. $(R = 0.0821 \ dm^3 \ atm \ K^{-1} \ mol^{-1})$

The temperature of a flask is increased from $27\,^{\circ}C$ to $277\,^{\circ}C$. If $0.1\,dm^{3}$ of gas bubbles out from the flask at $277\,^{\circ}C$,calculate the volume of the flask. (in $,dm^{3}$)

$A$ gas occupies $10 \ L$ at $STP$. Which of the following conditions will result in the same volume?

At temperature $T$,$1$ mole of $O_2$ gas (molar mass $32 \ g/mol$) is present in a container,exerting a pressure $P$. If $1$ mole of $He$ gas (molar mass $4 \ g/mol$) is placed in an identical container at temperature $2T$,what will be the pressure exerted by the $He$ gas?

$A$ student forgot to add the reaction mixture to the round bottomed flask at $27^{\circ} C$ but instead he/she placed the flask on the flame. After a lapse of time,he realized his mistake,and using a pyrometer he found the temperature of the flask was $477^{\circ} C$. What fraction of air would have been expelled out?