Calculate the standard enthalpy change for the synthesis of ammonia gas from the following data:
$i$. $2 H_{2(g)} + N_{2(g)} \longrightarrow N_{2}H_{4(g)}$; $\Delta_{r}H_{1}^{0} = 95.4 \ kJ$
$ii$. $N_{2}H_{4(g)} + H_{2(g)} \longrightarrow 2 NH_{3(g)}$; $\Delta_{r}H_{2}^{0} = -187.6 \ kJ$ (in $kJ$)

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

Find the value of $x$ in $\text{kJ}$ using the following equations:
$H_2O_{(g)} + C_{(s)} \to CO_{(g)} + H_{2(g)} : \Delta H = 131 \ \text{kJ}$
$CO_{(g)} + \frac{1}{2} O_{2(g)} \to CO_{2(g)} : \Delta H = -282 \ \text{kJ}$
$H_{2(g)} + \frac{1}{2} O_{2(g)} \to H_2O_{(g)} : \Delta H = -242 \ \text{kJ}$
$C_{(s)} + O_{2(g)} \to CO_{2(g)} : \Delta H = x \ \text{kJ}$

At $300 \, K$,the standard enthalpies of formation of $C_6H_5COOH_{(s)}$,$CO_{2_{(g)}}$,and $H_2O_{(l)}$ are $-408$,$-393$,and $-286 \, kJ \, mol^{-1}$ respectively. What is the heat of combustion of benzoic acid at constant volume in $kJ$ (in $.75$)? $(R = 8.31 \, J \, mol^{-1} \, K^{-1})$

When $600 \; mL$ of $0.2 \; M \; HNO_3$ is mixed with $400 \; mL$ of $0.1 \; M \; NaOH$ solution in a flask,the rise in temperature of the flask is $\dots \times 10^{-2} \; ^{\circ}C$. (Enthalpy of neutralisation $= 57 \; kJ \; mol^{-1}$ and Specific heat of water $= 4.2 \; J \; K^{-1} \; g^{-1}$) (Neglect heat capacity of flask)

Which of the following is an exothermic reaction?