If the $\Delta H_{fusion}$ of a substance is $'x'$ and $\Delta H_{vap}$ is $'y'$,then $\Delta H_{sublimation}$ will be:

One mole of $C_2H_5OH_{(l)}$ was completely burnt in oxygen to form $CO_{2(g)}$ and $H_2O_{(l)}$. The standard enthalpy of formation $\Delta_fH^{\ominus}$ of $C_2H_5OH_{(l)}, CO_{2(g)}$ and $H_2O_{(l)}$ is $x, y, z \ kJ \ mol^{-1}$ respectively. What is $\Delta_rH^{\ominus}$ (in $kJ \ mol^{-1}$) for this reaction?

The value of the enthalpy of neutralization of an acid and a base is significant only when $......$

The enthalpy of atomisation for the reaction $CH_{4(g)} \to C_{(g)} + 4H_{(g)}$ is $1665 \ kJ \ mol^{-1}$. What is the bond energy of $C-H$ bond?

Calculate the enthalpy change of the reaction for $H_2(g) + Cl_2(g) \rightarrow 2HCl(g)$, given the bond energies (in $\text{kJ mol}^{-1}$): $H-H = 436$, $Cl-Cl = 242$, $H-Cl = 431$.

Given the thermochemical reactions:
$C(\text{graphite}) + \frac{1}{2} O_{2(g)} \to CO_{(g)}; \Delta H = -110.5 \ kJ$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \to CO_{2(g)}; \Delta H = -283.2 \ kJ$
Calculate the heat of reaction for $C(\text{graphite}) + O_{2(g)} \to CO_{2(g)}$ in $kJ$.