Thermochemistry

From the data of following bond energies:

 $\begin{array}{l}H-Hbondenergy:431.37kJmo{l}^{-1}\\ C=Cbondenergy:606.10kJmo{l}^{-1}\\ C-Cbondenergy:336.49kJmo{l}^{-1}\\ C-Hbondenergy:410.50kJmo{l}^{-1}\end{array}$

Calculate the enthalpy of the following reaction in $kJmo{l}^{-1}$.

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 number of endothermic process/es from the following is _______.

A. ${\mathrm{I}}_2( \mathrm{g})\to 2\mathrm{I}\left(\mathrm{g}\right)$

B. $\mathrm{HCl}\left(\mathrm{g}\right)\to \mathrm{H}\left(\mathrm{g}\right)+\mathrm{Cl}\left(\mathrm{g}\right)$

C. ${\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

D. $\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2( \mathrm{g})\to {\mathrm{CO}}_2( \mathrm{g})$

E. Dissolution of ammonium chloride in water

${\mathrm{A}}_2+{\mathrm{B}}_2\to 2\mathrm{AB}.\Delta {\mathrm{H}}_{\mathrm{f}}=-200 \mathrm{kJ} {\mathrm{mol}}^{-1}$

$\mathrm{AB}, {\mathrm{A}}_2$ and ${\mathrm{B}}_2$ are diatomic molecules. If the bond enthalpies of ${\mathrm{A}}_2, {\mathrm{B}}_2$ and $\mathrm{AB}$ are in the ratio$1:0.5:1,$ then the bond enthalpy of ${\mathrm{A}}_2$ is$\mathrm{\_\_\_\_\_\_\_\_\_kJ} {\mathrm{mol}}^{–1}$ (Nearest integer)

Solid fuel used in rocket is a mixture of ${\mathrm{Fe}}_2{\mathrm{O}}_3$and $\mathrm{Al}$ (in ratio $1 : 2$). The heat evolved $\left(\mathrm{kJ}\right)$ per gram of the mixture is _____ (Nearest integer)

Given ${\mathrm{\Delta H}}_{\mathrm{f}}^0\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)=-1700 \mathrm{kJ} {\mathrm{mol}}^{-1}$

${\mathrm{\Delta H}}_{\mathrm{f}}^0\left({\mathrm{Fe}}_2{\mathrm{O}}_3\right)=-840 \mathrm{kJ} {\mathrm{mol}}^{-1}$

Molar mass of $\mathrm{Fe}, \mathrm{AI}$ and $\mathrm{O}$ are $56, 27$ and $16 \mathrm{g} {\mathrm{mol}}^{–1}$ respectively

Consider the following data

Heat of combustion of ${\mathrm{H}}_2\left(\mathrm{g}\right)=–241.8 \mathrm{kJ} {\mathrm{mol}}^{–1}$

Heat of combustion of $\mathrm{C}\left(\mathrm{s}\right)=–393.5 \mathrm{kJ} {\mathrm{mol}}^{–1}$

Heat of combustion of  ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)$$=–1234.7 \mathrm{kJ} {\mathrm{mol}}^{–1}$

The heat of formation of ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)$ is $(–)$ _____ $\mathrm{kJ} {\mathrm{mol}}^{–1}$ (Nearest integer).

Given

(A) $2\mathrm{CO}\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{CO}}_2\left(\mathrm{g}\right) {\mathrm{\Delta H}}_1^{\mathrm{o}}=-\mathrm{x} \mathrm{kJ} {\mathrm{mol}}^{-1}$

(B) $\mathrm{C}\left(\mathrm{graphite}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right) {\mathrm{\Delta H}}_2^{\mathrm{o}}=-\mathrm{y} \mathrm{kJ} {\mathrm{mol}}^{-1}$

The $∆{\mathrm{H}}^{\mathrm{o}}$ for the reaction $\mathrm{C}\left(\mathrm{graphite}\right)+\frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)\to \mathrm{CO}\left(\mathrm{g}\right)$ is

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 ${\mathrm{C}}_2{\mathrm{H}}_6 \mathrm{and} {\mathrm{C}}_3{\mathrm{H}}_8.$

Determine the enthalpy change for the given reaction:

${\mathrm{CH}}_4\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{CH}}_3\mathrm{Cl}\left(\mathrm{g}\right)+\mathrm{HCl}\left(\mathrm{g}\right)$

Bond energies are given as below:

$$\begin{gathered} \mathrm{C}-\mathrm{H} = 412 \mathrm{kJ} {\mathrm{mol}}^{-1} \mathrm{C}-\mathrm{Cl}= 338 \mathrm{kJ} {\mathrm{mol}}^{-1} \\ \mathrm{Cl}-\mathrm{Cl}= 242 \mathrm{kJ} {\mathrm{mol}}^{-1} \mathrm{H}-\mathrm{Cl}= 431 \mathrm{kJ} {\mathrm{mol}}^{-1} \end{gathered}$$

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:

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

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

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

Heat of combustion of naphthalene is $-1230 \mathrm{kcal}/\mathrm{mol}$ at constant volume and $25°\mathrm{C}$. What will be the heat of combustion of the reaction at constant pressure and $25°C$ ?