$C + 2S \rightarrow CS_2$; $\Delta H^o = +117 \, kJ \, mol^{-1}$; $C + O_2 \rightarrow CO_2$; $\Delta H^o = -393 \, kJ \, mol^{-1}$; $S + O_2 \rightarrow SO_2$; $\Delta H^o = -297 \, kJ \, mol^{-1}$. The heat of combustion of $CS_2$ in $kJ \, mol^{-1}$ is:

The heat of neutralization of a strong acid with a strong base is constant and is equal to:

Calculate the $N-N$ bond energy in $N_2H_4$ from the given bond enthalpy data.
$\varepsilon_{N-H} = 393 \ kJ/mol$
$\varepsilon_{H-H} = 436 \ kJ/mol$
$\Delta H_{vap}[N_2H_{4(l)}] = 18 \ kJ/mol$
$N_2H_{4(l)} + H_{2(g)} \to 2NH_{3(g)} : \Delta H = -142 \ kJ/mol$
....... $kJ/mol$

Diborane is formed from the elements as shown in equation $(i)$:
$2 B_{(s)} + 3 H_{2(g)} \longrightarrow B_2H_{6(g)} \dots (i)$
Given that:
$H_2O_{(l)} \longrightarrow H_2O_{(g)}, \quad \Delta H_1^{\circ} = 44 \, kJ$
$2 B_{(s)} + \frac{3}{2} O_{2(g)} \longrightarrow B_2O_{3(s)}, \quad \Delta H_2^{\circ} = -1273 \, kJ$
$B_2H_{6(g)} + 3 O_{2(g)} \longrightarrow B_2O_{3(s)} + 3 H_2O_{(g)}, \quad \Delta H_3^{\circ} = -2035 \, kJ$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \longrightarrow H_2O_{(l)}, \quad \Delta H_4^{\circ} = -286 \, kJ$
The $\Delta H^{\circ}$ for the reaction $(i)$ is $..... \, kJ$.

The average $C-H$ bond energy is $416 \ kJ \ mol^{-1}$. Which of the following equations correctly represents the bond dissociation of $CH_4$?

The heats of solution of anhydrous $CuSO_4$ and $CuSO_4 \cdot 5H_2O$ are $-15.89 \, kcal \, mol^{-1}$ and $2.80 \, kcal \, mol^{-1}$ respectively. What is the heat of hydration of anhydrous $CuSO_4$ in $kcal \, mol^{-1}$?