For an endothermic reaction where $\Delta H$ represents the enthalpy of the reaction in $kJ/mole$,the minimum value for the energy of activation $(E_a)$ will be:

Calculate the standard internal energy change for $OF_{2(g)} + H_2O_{(g)} \longrightarrow 2 HF_{(g)} + O_{2(g)}$ at $300 \ K$,if $\Delta_{f} H^{\circ}$ of $OF_{2(g)}$,$H_2O_{(g)}$,and $HF_{(g)}$ are $20$,$-250$,and $-270 \ kJ \ mol^{-1}$ respectively. $[R = 8.314 \ J \ K^{-1} \ mol^{-1}]$ (in $kJ$)

At the temperature $T$ $(K)$ for the reaction: $X_2O_{4(l)} \rightarrow 2XO_{2(g)}$,given $\Delta U = x \ kJ \ mol^{-1}$ and $\Delta S = y \ J \ K^{-1} \ mol^{-1}$. The Gibbs energy change for the reaction is: (Assume $X_2O_4$ and $XO_2$ are ideal gases)

Arrange the following in order of magnitude of work done by the system / on the system at constant temperature:
$(a)$ $|w_{reversible}|$ for expansion in infinite stage.
$(b)$ $|w_{irreversible}|$ for expansion in single stage.
$(c)$ $|w_{reversible}|$ for compression in infinite stage.
$(d)$ $|w_{irreversible}|$ for compression in single stage.
Choose the correct answer from the options given below:

For the reaction: $A_{(g)} + B_{(s)} \rightleftharpoons 2C_{(g)} + D_{(g)}$,given $\Delta U = 5.0 \ kcal$ and $\Delta S = 50 \ cal \ K^{-1}$ at $400 \ K$. Calculate $\Delta G$ for the reaction. (in $kcal$)

An ideal gas in a thermally insulated vessel at internal pressure $= P_1$,volume $= V_1$ and absolute temperature $= T_1$ expands irreversibly against zero external pressure,as shown in the diagram. The final internal pressure,volume and absolute temperature of the gas are $P_2, V_2$ and $T_2$,respectively. For this expansion,
$(A) \ q = 0$
$(B) \ T_2 = T_1$
$(C) \ P_2 V_2 = P_1 V_1$
$(D) \ P_2 V_2^\gamma = P_1 V_1^\gamma$