Given that $$\mathrm{C}_{(\mathrm{g})}+4 \mathrm{H}_{(\mathrm{g})} \longrightarrow \mathrm{CH}_{4(\mathrm{g})} \Delta \mathrm{H}^{\circ}=-1665 \mathrm{~kJ}$$

What is bond energy per mole of $\mathrm{C}-\mathrm{H}$ bond?

If bond formation energy of $\mathrm{H}-\mathrm{H}$ bond is $-433 \mathrm{~kJ} \mathrm{~mol}^{-1}$ find the bond dissociation energy for 0.5 mole $H_{2(g)}$.

What is the value of standard enthalpy of formation of dihydrogen?

Calculate Gibbs energy change for a reaction having $\Delta \mathrm{H}=31400 \mathrm{~J}, \Delta \mathrm{~S}=32 \mathrm{~J} \mathrm{~K}^{-1}$ at $1000^{\circ} \mathrm{C}$ ?