Any series of operations so carried out that at the end,the system is back to its initial state is called:

$A$ 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:

In thermodynamics,a process is reversible when:

For the process to occur under adiabatic conditions,the correct condition is:

The value of $\Delta H - \Delta E$ for the following reaction at $27 \ ^\circ C$ will be $2NH_{3(g)} \to N_{2(g)} + 3H_{2(g)}$

One mole of an ideal gas at $25\,^{\circ}C$ expands its volume from $1\,L$ to $4\,L$ at constant temperature. What work (in $J$) is done if the gas expands against a vacuum $(P_{ext} = 0)$?