Following data is known about the melting of a compound $AB$: $\Delta H = 9.2 \ kJ \ mol^{-1}$,$\Delta S = 0.008 \ kJ \ K^{-1} \ mol^{-1}$. Its melting point is:

For a dimerization reaction,$2 A_{(g)} \rightarrow A_{2(g)}$ at $298 \ K$,$\Delta U^{\ominus} = -20 \ kJ \ mol^{-1}$,$\Delta S^{\ominus} = -30 \ J \ K^{-1} \ mol^{-1}$,then the $\Delta G^{\ominus}$ will be........ $J$

Identify the correct statements from the following.
$I$. At $0 \ K$,the entropy of pure crystalline materials approaches zero.
$II$. Entropy for the process,$H_2O_{(l)} \longrightarrow H_2O_{(g)}$ decreases.
$III$. Gibbs' energy is a state function.

The molar heat capacity $(C_p)$ of $CD_2O$ is $10 \, cal \, K^{-1} \, mol^{-1}$ at $1000 \, K$. The change in entropy associated with cooling of $32 \, g$ of $CD_2O$ vapour from $1000 \, K$ to $100 \, K$ at constant pressure will be.....$cal \, deg^{-1}$ ($D = $ deuterium,atomic mass $= 2 \, u$)

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

Three moles of an ideal gas are expanded isothermally from a volume of $300 \ cm^3$ to $2.5 \ L$ at $300 \ K$ against a constant external pressure of $1.9 \ atm$. The work done in joules is: