The Enthalpy of combustion of $$\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOH}(\mathrm{s})$$ at $$25^{\circ} \mathrm{c}$$ and 1.0 atm pressure is $$-2546 \mathrm{~kJ} / \mathrm{mol}$$. What is the Internal energy change for this reaction?

Given :

$$ \begin{gathered} \Delta \mathrm{H}^0 \mathrm{f}_{\text {of }} \mathrm{CO}_2(\mathrm{~g})=-393.5 \mathrm{~kJ} / \mathrm{mol} \\ \Delta \mathrm{H}^0{ }_{\mathrm{f}} \text { of } \mathrm{H}_2 \mathrm{O}(\mathrm{l})=-286 \mathrm{~kJ} / \mathrm{mol} \\ \Delta \mathrm{H}^0{ }_{\mathrm{f}} \text { of } \mathrm{C}_3 \mathrm{H}_6(\mathrm{~g})=+20.6 \mathrm{~kJ} / \mathrm{mol} \end{gathered} $$

$$\Delta \mathrm{H}^0$$ isomerisation of Cyclopropane to Propene $$=-33 \mathrm{~kJ} / \mathrm{mol}$$

What is the standard enthalpy of combustion of Cyclopropane?

5.0 moles of an Ideal gas at 3.0 atm pressure and $$27^{\circ} \mathrm{C}$$ is compressed isothermally to half its volume by application of an external pressure of $$3.5 \mathrm{~atm}$$. What is the amount of work done (in joules) on the gas? Given: $$1 \mathrm{~L} \mathrm{~atm}=101.3 \mathrm{~J}: \mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}{ }^{-1} \mathrm{~mol}^{-1}$$

The standard enthalpy of formation of $$\mathrm{CH}_4$$, the standard enthalpy of sublimation of Carbon and the bond dissociation enthalpy of Hydrogen gas are $$-74.8,+719.6$$ and $$436 \mathrm{~kJ} / \mathrm{mol}$$ respectively. What is the bond enthalpy of $$\mathrm{C}-\mathrm{H}$$ bond in Methane?