The enthalpy of vaporization of a liquid at $500 \, K$ and $1 \, atm$ pressure is $10 \, kcal \, mol^{-1}$. The change in internal energy $(\Delta U)$ for $3 \, moles$ of the liquid at the same temperature and pressure is ............ $kcal$.

The enthalpies of formation of gaseous $N_2O$ and $NO$ at $298 \ K$ are $82.0$ and $90.0 \ kJ \ mol^{-1}$ respectively. The enthalpy change of the reaction $N_2O_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow 2 NO_{(g)}$ is

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 process $H_2O_{(l)} (1 \ bar, 373 \ K) \rightarrow H_2O_{(g)} (1 \ bar, 373 \ K)$,the correct set of thermodynamic parameters is:

Calculate $\Delta H^{\circ}$ for the reaction, $Na_2O_{(s)} + SO_{3(g)} \longrightarrow Na_2SO_{4(s)}$, given the following reactions:
$(A) \ Na_{(s)} + H_2O_{(l)} \longrightarrow NaOH_{(s)} + \frac{1}{2}H_{2(g)} \quad \Delta H^{\circ} = -146 \ kJ$
$(B) \ Na_2SO_{4(s)} + H_2O_{(l)} \longrightarrow 2NaOH_{(s)} + SO_{3(g)} \quad \Delta H^{\circ} = +418 \ kJ$
$(C) \ 2Na_2O_{(s)} + 2H_{2(g)} \longrightarrow 4Na_{(s)} + 2H_2O_{(l)} \quad \Delta H^{\circ} = +259 \ kJ$

Identify the correct statement from the following regarding a chemical reaction.