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

For the combustion reaction $2C_8H_{18}(g) + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$,what are the signs of $\Delta H$,$\Delta S$,and $\Delta G$?

For a certain thermochemical reaction $M \rightarrow N$ at $T = 400 \ K$,$\Delta H^{\ominus} = 77.2 \ kJ \ mol^{-1}$ and $\Delta S = 122 \ J \ K^{-1} \ mol^{-1}$,the value of $\log K$ is $ . . . . . . \times 10^{-1}$.

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

The heats of combustion of $C_2H_4, C_2H_6$ and $H_2$ are $-1409.5 \, kJ, -1558.3 \, kJ$ and $-285.6 \, kJ$ respectively. The heat of hydrogenation of ethene is ...... $kJ$.

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)