One mole of an ideal monoatomic gas is heated in a process $PV^{5/2} = \text{constant}$. The amount of heat absorbed in the process for a $36 \ ^\circ C$ rise in temperature is (in $cal$):

An ideal gas is expanded from $(p_1, V_1, T_1)$ to $(p_2, V_2, T_2)$ under different conditions. The correct statement$(s)$ among the following is(are):
[$A$] The work done on the gas is maximum when it is compressed irreversibly from $(p_2, V_2)$ to $(p_1, V_1)$ against constant pressure $p_1$.
[$B$] The work done by the gas is less when it is expanded reversibly from $V_1$ to $V_2$ under adiabatic conditions as compared to that when expanded reversibly from $V_1$ to $V_2$ under isothermal conditions.
[$C$] The change in internal energy of the gas is $(i)$ zero,if it is expanded reversibly with $T_1=T_2$,and $(ii)$ positive,if it is expanded reversibly under adiabatic conditions with $T_1 \neq T_2$.
[$D$] If the expansion is carried out freely,it is simultaneously both isothermal as well as adiabatic.

An isolated box,equally partitioned,contains two ideal gases $A$ and $B$ as shown in the figure. When the partition is removed,the gases mix. The changes in enthalpy $(\Delta H)$ and entropy $(\Delta S)$ in the process,respectively,are

For the reactions,$C + O_2 \to CO_2; \Delta H = -393 \ J$
$2Zn + O_2 \to 2ZnO; \Delta H = -412 \ J$

$C_{(s)} + 2 H_{2(g)} \rightarrow CH_{4(g)}$; $\Delta H = -74.8 \ kJ \ mol^{-1}$
Which of the following diagrams gives an accurate representation of the above reaction?
[$R \rightarrow$ reactants; $P \rightarrow$ products]

$10 \ g$ each of $NH_3, N_2, Cl_2$ and $H_2S$ are expanded isothermally and reversibly at the same temperature. Identify the gas that performs maximum work.