Which of the following is an extensive property of a system?

The work done during the expansion of $1 \ mol$ of an ideal gas into a vacuum is ............ .

The energy diagram for a reaction $R \to P$ is shown below. The $\Delta H^o$ for the reaction will be:

The enthalpies of all elements in their standard states are:

$A$ gas is allowed to expand against a constant external pressure of $2.5 \ bar$ from an initial volume of $2.5 \ L$ to a final volume of $4.5 \ L$. What is the amount of work done (in $J$)?

Which among the following is $NOT$ a feature of a reversible process?