Given that $H_{2(g)} + 1/2 O_{2(g)} \to H_2O_{(g)}; \Delta H_1$ and $H_{2(g)} + 1/2 O_{2(g)} \to H_2O_{(l)}; \Delta H_2$,which of the following is correct?

$C_{(diamond)} + O_2 \to CO_2; \Delta H = -395.3 \ kJ/mole$
$C_{(graphite)} + O_2 \to CO_2; \Delta H = -393.4 \ kJ/mole$
$C_{(graphite)} \to C_{(diamond)}; \Delta H = ?$

The standard enthalpy of atomization of ethane according to the equation $C_2H_{6(g)} \rightarrow 2C_{(g)} + 6H_{(g)}$ is $622 \ kJ \ mol^{-1}$. If the standard mean $C-H$ bond dissociation enthalpy is $90 \ kJ \ mol^{-1}$,the standard mean dissociation enthalpy of the $C-C$ bond (in $kJ \ mol^{-1}$) is:

For the reaction $2 H_2 + O_2 \rightarrow 2 H_2 O$,$\Delta H = -571 \ kJ$. Bond energy of $H-H = 435 \ kJ$ and $O=O = 498 \ kJ$. Then the average bond energy of $O-H$ bond will be:

What is the heat of atomisation of $P_4O_{6(s)}$?
Given that the heat of sublimation of $P_4O_6$ is $x \ kJ/mol$ and the $P-O$ bond energy is $y \ kJ/mol$.

What is the enthalpy change when $6.80 \, g$ of $NH_3$ is passed over hot $CuO$ (in $, kJ$)? The standard enthalpies of formation for $NH_3(g)$,$CuO(s)$,and $H_2O(l)$ are $-46.0$,$-155.0$,and $-285.0 \, kJ \, mol^{-1}$ respectively. The reaction is: $NH_3(g) + \frac{3}{2}CuO(s) \to \frac{1}{2}N_2(g) + \frac{3}{2}H_2O(l) + \frac{3}{2}Cu(s)$