Enthalpy Change of a Reaction- Reaction Enthalpy

Consider the following reactions

(i) ${\text{H}}_{\left(\text{aq}\right)}^{+}+{\text{OH}}_{\left(\text{aq}\right)}^{-}\to {\text{H}}_2\text{O}\left(\mathrm{\ell \; }\right)$

$\Delta \text{H}=-{\text{X}}_1{\text{ k J mol}}^{-1}$

(ii) ${\text{H}}_2\left(\text{g}\right)+\frac{1}{2}{\text{O}}_2\left(\text{g}\right)\to {\text{H}}_2\text{O}\left(\ell \right)$

$\Delta \text{H}=-{\text{X}}_2{\text{ k J mol}}^{-1}$

(iii) ${\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)\to \mathrm{CO}\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

$\Delta \text{H}=-{\text{X}}_3{\text{ k J mol}}^{-1}$

(iv) ${\text{C}}_2{\text{H}}_2\left(\text{g}\right)+\frac{5}{2}{\text{O}}_2\left(\text{g}\right)\to 2{\text{CO}}_2\left(\text{g}\right)+{\text{H}}_2\text{O}\left(\ell \right)$

$\Delta \text{H}=+4{\text{X}}_4{\text{ k J mol}}^{-1}$

Enthalpy of formation of ${\text{H}}_2\text{O}\left(\ell \right)$

Bond dissociation enthalpy of  $H_2,C{l}_{\mathrm{2 }}\mathrm{and}HCl\mathrm{ are }434,242\mathrm{ and} \mathrm{431 }\mathrm{k}\mathrm{J}\mathrm{ m}\mathrm{o}{\mathrm{l}}^{-1}$ respectively. The enthalpy of formation of HCl is:  

What is enthalpy of hydration ?

The values of enthalpy of formation for the compounds${\mathrm{C}}_2{\mathrm{H}}_6\left(\mathrm{g}\right), {\mathrm{C}}_3{\mathrm{H}}_8\left(\mathrm{g}\right), {\mathrm{CO}}_2\left(\mathrm{g}\right) \mathrm{and} {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \mathrm{are} -84.6, -107.6, -393.5 \mathrm{and} -285.8 \mathrm{kJ} \mathrm{mol}{ }^{-1 }$ respectively. Find out which one is better fuel between ${\mathrm{C}}_2{\mathrm{H}}_6 \mathrm{and} {\mathrm{C}}_3{\mathrm{H}}_8.$

Calculate the change in enthalpy for the following process at $1$ atm

${\mathrm{H}}_2\mathrm{O}(\mathrm{l},{150}^{\mathrm{o}}\mathrm{C})\to {\mathrm{H}}_2\mathrm{O}(\mathrm{g},{150}^{\mathrm{o}}\mathrm{C})$ given that $∆{\mathrm{H}}_{\mathrm{\vartheta }} \mathrm{at} {100}^{\mathrm{o}}\mathrm{C} \mathrm{is} 40.7 \mathrm{kJ} {\mathrm{mol}}^{-1}$

$$\begin{gathered} {\mathrm{C}}_{\mathrm{P}}({\mathrm{H}}_2\mathrm{O},\mathrm{l})=75.0\mathrm{J} {\mathrm{mol}}^{-1}{\mathrm{K}}^{-1} \\ {\mathrm{C}}_{\mathrm{P}}({\mathrm{H}}_2\mathrm{O},\mathrm{g})=33.3\mathrm{J} {\mathrm{mol}}^{-1}{\mathrm{K}}^{-1} \end{gathered}$$

For the reaction,

${\mathrm{PCl}}_3\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{PCl}}_5\left(\mathrm{g}\right), ∆\mathrm{H}=-\mathrm{x} \mathrm{kJ}$

If the $∆{{\mathrm{H}}_{\mathrm{f}}}^{\mathrm{o}} {\mathrm{PCl}}_3 \mathrm{is} -\mathrm{y} \mathrm{kJ}$ what is $∆{{\mathrm{H}}_{\mathrm{f}}}^{\mathrm{o}} {\mathrm{PCl}}_5 \mathrm{is} -\mathrm{y} \mathrm{kJ}$ ?

Find the $∆\mathrm{H}$ for the reaction below, given the following reactions and subsequent $∆\mathrm{H}$ values:

${\mathrm{PCl}}_5\left(\mathrm{g}\right)\to {\mathrm{PCl}}_3\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)$

${\mathrm{P}}_4\left(\mathrm{s}\right)+6{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 4{\mathrm{PCl}}_3\left(\mathrm{g}\right) ∆\mathrm{H}=-2439 \mathrm{kJ}$

$4{\mathrm{PCl}}_5\left(\mathrm{g}\right)\to {\mathrm{P}}_4\left(\mathrm{s}\right)+10{\mathrm{Cl}}_2\left(\mathrm{g}\right) ∆\mathrm{H}=3438 \mathrm{kJ}$

The combustion of one mole of benzee takes place at $298\mathrm{K}$ and $1$atm. After combustion,${\mathrm{CO}}_2$(g) and ${\mathrm{H}}_2\mathrm{O}$(l) are produced and $3267.0\mathrm{KJ}$ of heat is liberated. Calculate the standard ethalpy of formation, ${\mathrm{\Delta }}_{\mathrm{f}}{\mathrm{H}}^{\ominus }$ of benzene.

Stadard enthalpies of formation of ${\mathrm{CO}}_2$(g) and${\mathrm{H}}_2\mathrm{O}$(l) are $-393.5\mathrm{Kj} {\mathrm{mol}}^{-1 }$and $-285.83 \mathrm{KJ} {\mathrm{mol}}^{-1 }$respectively.

In which of the following process of neutralisation, $∆{\mathrm{H}}_{\mathrm{neutralisation}}$ is less than heat of formation of water from its ions?

The standard enthalpy of combustion of cyclopropane is -2091 kJ/mole at 25oC then calculate the enthalpy of formation of cyclopropane. If ΔHof(CO2) = -393.5 kJ/mol and ΔH of(H2O) = -285.8 kJ/mol.

For the reaction, ${\mathrm{PCl}}_3\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{PCl}}_5\left(\mathrm{g}\right)$$∆\mathrm{H}=-\mathrm{xKJ}$

If the ${{\mathrm{H}}^{\mathrm{o}}}_{\mathrm{f}}{\mathrm{PCl}}_3$ is $-\mathrm{yKJ}$ what is ${{\mathrm{H}}^{\mathrm{o}}}_{\mathrm{f}} {\mathrm{PCl}}_5$?

Calculate the ${{\mathrm{\Delta H}}_{\mathrm{f}}}^{\mathrm{o}}$ of${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6{}_{\left(\mathrm{s}\right)}$from the following data:
$$\begin{gathered} {\mathrm{\Delta H}}_{\mathrm{comb}}[{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6{}_{\left(\mathrm{s}\right)}]=-2816 \mathrm{kJ}/\mathrm{mol} \\ {{\mathrm{\Delta H}}_{\mathrm{f}}}^{\mathrm{o}} \mathrm{of} {{\mathrm{CO}}_2}_{\left(\mathrm{g}\right)}=-393.5 \mathrm{kJ}/\mathrm{mol} \\ {{\mathrm{\Delta H}}_{\mathrm{f}}}^{\mathrm{o}} \mathrm{of} {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)=-285.9 \mathrm{kJ}/\mathrm{mol} \end{gathered}$$

If heat of dissociation of ${\mathrm{CHCl}}_2\mathrm{COOH} \mathrm{is} 0.7 \mathrm{kcal}/\mathrm{mole}$ then ΔH for the reaction:
${\mathrm{CHCl}}_2\mathrm{COOH}+\mathrm{KOH}\to {\mathrm{CHCl}}_2\mathrm{COOK}+{\mathrm{H}}_2\mathrm{O}$
 

Which of the following represents heat of formation $\left({\mathrm{\Delta H}}_{\mathrm{f}}\right) ?$

If $9.8 \mathrm{g}$ of ${\mathrm{H}}_2{\mathrm{SO}}_4$ is neutralised exactly with strong alkali the heat evolved is: ($∆\mathrm{H}$ of neutralisation is $13.6 \mathrm{k} \mathrm{cal}$)

Calculate the standard enthalpy of formation of liquid benzene. Given the enthalpies of combustion of carbon$\left(\mathrm{s}\right)$, hydrogen (g) and benzene(l) are $-393.5 \mathrm{kJ}, -285.83 \mathrm{kJ} \mathrm{and} -3267 \mathrm{kJ}$ respectively