Based on the first law of thermodynamics,which one of the following is correct?

$A$ gas is allowed to expand in a well-insulated container against a constant external pressure of $2.5 \ atm$ from an initial volume of $2.50 \ L$ to a final volume of $4.50 \ L$. The change in internal energy $\Delta U$ of the gas in joules will be .............. $J$.

For combustion of one mole of magnesium in an open container at $300 \ K$ and $1 \ bar$ pressure,$\Delta_{C}H^{\ominus} = -601.70 \ kJ \ mol^{-1}$,the magnitude of change in internal energy for the reaction is $.... \ kJ$. (Nearest integer)
(Given : $R = 8.3 \ J \ K^{-1} \ mol^{-1}$ )

$A$ gas occupies a volume of $2 \ L$ at $S.T.P.$ It absorbs $300 \ J$ of heat. If the pressure is $1 \ atm$,the volume becomes $2.5 \ L$. The change in internal energy $(\Delta U)$ for the process in $Joule$ is:

For the reaction $3O_{2(g)} \rightarrow 2O_{3(g)}$,the value of $\Delta U - \Delta H$ is equal to .....

If $100 \ L$ of an ideal gas at a pressure of $2 \ atm$ is compressed isothermally and reversibly to a final volume of '$X$' $L$ and releases $460.6 \ L \ atm$ of heat,the final volume '$X$' (in $L$) is