Which of the following thermodynamic properties is a path function?

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

Fill in the blanks:
$(i)$ $A$ system that allows the exchange of energy but not matter with the surroundings is called a ........ .
$(ii)$ The total amount of energy consisting of the internal energy of a substance plus the product of its pressure and volume is called ........ .
$(iii)$ The change in energy that occurs when a chemical reaction is carried out at constant pressure is called ........ .

$1 \, mol$ of an ideal gas is compressed reversibly at a constant temperature of $27 \, ^oC$ from $1 \, bar$ to $4 \, bar$. Calculate the work done in $kJ$.

Among the following,the state function$(s)$ is(are):
$A$. Internal energy
$B$. Irreversible expansion work
$C$. Reversible expansion work
$D$. Molar enthalpy

$A$ given mass of gas expands from state $A$ to state $B$ by three paths $1, 2$ and $3$ as shown in the figure. If $w_1, w_2$ and $w_3$ are the work done by the gas along the three paths respectively,then: