04. Bond Energy
Thermodynamics

273030 The bond dissociation enthalpy of gaseous $\mathrm{H}_2$ $\mathrm{Cl}_2$ and $\mathrm{HCl}$ are 435,243 and $431 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{Y}}$ respectively. In the same unit, enthalpy of formation of $\mathrm{HCl}$ gas is

1 -92
2 -184
3 +92
4 +184
Thermodynamics

273031 The $\mathrm{H}-\mathrm{H}$ bond energy is $430 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{Cl}$ $-\mathrm{Cl}$ bond energy is $240 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}, \Delta \mathrm{H}$ for $\mathrm{HCl}$ is $-90 \mathrm{~kJ}$, The $\mathrm{H}-\mathrm{Cl}$ bond energy is about :

1 $180 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $360 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $213 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $425 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273032 $\mathrm{CH}_2=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_3-\mathrm{CH}_3(\mathrm{~g})$
The heat of reaction is [bond energy of $\mathrm{C}-\mathrm{C}=80 \mathrm{kcal}, \mathrm{C}=\mathrm{C}=145 \mathrm{kcal}$,
$\mathrm{C}-\mathrm{H}=98 \mathrm{kcal}, \mathbf{H}-\mathrm{H}=103 \mathrm{kcal}]$

1 $-14 \mathrm{kcal}$
2 $-28 \mathrm{kcal}$
3 $-42 \mathrm{kcal}$
4 $-56 \mathrm{kcal}$
Thermodynamics

273038 The following reaction is performed at $298 \mathrm{~K}$ $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \to \mathrm{NO}_2(\mathrm{~g})$
The standard free energy of formation of $\mathrm{NO}(\mathrm{g})$ is $86.6 \mathrm{~kJ} / \mathrm{mol}$ at $298 \mathrm{~K}$. What is the standard free energy of formation of $\mathrm{NO}_2(g)$ at $298 \mathrm{~K} ?\left(\mathrm{~K}_{\mathrm{p}}=1.6 \times 10^{12}\right)$

1 $\mathrm{R}(298)$ In $\left(1.6 \times 10^{12}\right)-86600$
2 $86600+\mathrm{R}(298) \operatorname{In}\left(1.6 \times 10^{12}\right)$
3 $86600-\frac{\operatorname{In}\left(1.6 \times 10^{12}\right)}{\mathrm{R}(298)}$
4 $0.5\left[2 \times 86600-\mathrm{R}(298) \ln \left(1.6 \times 10^{12}\right)\right]$
Thermodynamics

273040 The standard enthalpy of formation of $\mathbf{N H}_3$ is $46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. If the enthalpy of formation of $\mathrm{H}_2$ from its atoms is $-436 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and that of $\mathrm{N}_2$ is $-712 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond enthalpy of $\mathrm{N}-\mathrm{H}$ bond in $\mathrm{NH}_3$ is

1 $-964 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $+352 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273030 The bond dissociation enthalpy of gaseous $\mathrm{H}_2$ $\mathrm{Cl}_2$ and $\mathrm{HCl}$ are 435,243 and $431 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{Y}}$ respectively. In the same unit, enthalpy of formation of $\mathrm{HCl}$ gas is

1 -92
2 -184
3 +92
4 +184
Thermodynamics

273031 The $\mathrm{H}-\mathrm{H}$ bond energy is $430 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{Cl}$ $-\mathrm{Cl}$ bond energy is $240 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}, \Delta \mathrm{H}$ for $\mathrm{HCl}$ is $-90 \mathrm{~kJ}$, The $\mathrm{H}-\mathrm{Cl}$ bond energy is about :

1 $180 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $360 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $213 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $425 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273032 $\mathrm{CH}_2=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_3-\mathrm{CH}_3(\mathrm{~g})$
The heat of reaction is [bond energy of $\mathrm{C}-\mathrm{C}=80 \mathrm{kcal}, \mathrm{C}=\mathrm{C}=145 \mathrm{kcal}$,
$\mathrm{C}-\mathrm{H}=98 \mathrm{kcal}, \mathbf{H}-\mathrm{H}=103 \mathrm{kcal}]$

1 $-14 \mathrm{kcal}$
2 $-28 \mathrm{kcal}$
3 $-42 \mathrm{kcal}$
4 $-56 \mathrm{kcal}$
Thermodynamics

273038 The following reaction is performed at $298 \mathrm{~K}$ $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \to \mathrm{NO}_2(\mathrm{~g})$
The standard free energy of formation of $\mathrm{NO}(\mathrm{g})$ is $86.6 \mathrm{~kJ} / \mathrm{mol}$ at $298 \mathrm{~K}$. What is the standard free energy of formation of $\mathrm{NO}_2(g)$ at $298 \mathrm{~K} ?\left(\mathrm{~K}_{\mathrm{p}}=1.6 \times 10^{12}\right)$

1 $\mathrm{R}(298)$ In $\left(1.6 \times 10^{12}\right)-86600$
2 $86600+\mathrm{R}(298) \operatorname{In}\left(1.6 \times 10^{12}\right)$
3 $86600-\frac{\operatorname{In}\left(1.6 \times 10^{12}\right)}{\mathrm{R}(298)}$
4 $0.5\left[2 \times 86600-\mathrm{R}(298) \ln \left(1.6 \times 10^{12}\right)\right]$
Thermodynamics

273040 The standard enthalpy of formation of $\mathbf{N H}_3$ is $46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. If the enthalpy of formation of $\mathrm{H}_2$ from its atoms is $-436 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and that of $\mathrm{N}_2$ is $-712 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond enthalpy of $\mathrm{N}-\mathrm{H}$ bond in $\mathrm{NH}_3$ is

1 $-964 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $+352 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273030 The bond dissociation enthalpy of gaseous $\mathrm{H}_2$ $\mathrm{Cl}_2$ and $\mathrm{HCl}$ are 435,243 and $431 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{Y}}$ respectively. In the same unit, enthalpy of formation of $\mathrm{HCl}$ gas is

1 -92
2 -184
3 +92
4 +184
Thermodynamics

273031 The $\mathrm{H}-\mathrm{H}$ bond energy is $430 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{Cl}$ $-\mathrm{Cl}$ bond energy is $240 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}, \Delta \mathrm{H}$ for $\mathrm{HCl}$ is $-90 \mathrm{~kJ}$, The $\mathrm{H}-\mathrm{Cl}$ bond energy is about :

1 $180 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $360 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $213 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $425 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273032 $\mathrm{CH}_2=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_3-\mathrm{CH}_3(\mathrm{~g})$
The heat of reaction is [bond energy of $\mathrm{C}-\mathrm{C}=80 \mathrm{kcal}, \mathrm{C}=\mathrm{C}=145 \mathrm{kcal}$,
$\mathrm{C}-\mathrm{H}=98 \mathrm{kcal}, \mathbf{H}-\mathrm{H}=103 \mathrm{kcal}]$

1 $-14 \mathrm{kcal}$
2 $-28 \mathrm{kcal}$
3 $-42 \mathrm{kcal}$
4 $-56 \mathrm{kcal}$
Thermodynamics

273038 The following reaction is performed at $298 \mathrm{~K}$ $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \to \mathrm{NO}_2(\mathrm{~g})$
The standard free energy of formation of $\mathrm{NO}(\mathrm{g})$ is $86.6 \mathrm{~kJ} / \mathrm{mol}$ at $298 \mathrm{~K}$. What is the standard free energy of formation of $\mathrm{NO}_2(g)$ at $298 \mathrm{~K} ?\left(\mathrm{~K}_{\mathrm{p}}=1.6 \times 10^{12}\right)$

1 $\mathrm{R}(298)$ In $\left(1.6 \times 10^{12}\right)-86600$
2 $86600+\mathrm{R}(298) \operatorname{In}\left(1.6 \times 10^{12}\right)$
3 $86600-\frac{\operatorname{In}\left(1.6 \times 10^{12}\right)}{\mathrm{R}(298)}$
4 $0.5\left[2 \times 86600-\mathrm{R}(298) \ln \left(1.6 \times 10^{12}\right)\right]$
Thermodynamics

273040 The standard enthalpy of formation of $\mathbf{N H}_3$ is $46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. If the enthalpy of formation of $\mathrm{H}_2$ from its atoms is $-436 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and that of $\mathrm{N}_2$ is $-712 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond enthalpy of $\mathrm{N}-\mathrm{H}$ bond in $\mathrm{NH}_3$ is

1 $-964 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $+352 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273030 The bond dissociation enthalpy of gaseous $\mathrm{H}_2$ $\mathrm{Cl}_2$ and $\mathrm{HCl}$ are 435,243 and $431 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{Y}}$ respectively. In the same unit, enthalpy of formation of $\mathrm{HCl}$ gas is

1 -92
2 -184
3 +92
4 +184
Thermodynamics

273031 The $\mathrm{H}-\mathrm{H}$ bond energy is $430 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{Cl}$ $-\mathrm{Cl}$ bond energy is $240 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}, \Delta \mathrm{H}$ for $\mathrm{HCl}$ is $-90 \mathrm{~kJ}$, The $\mathrm{H}-\mathrm{Cl}$ bond energy is about :

1 $180 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $360 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $213 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $425 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273032 $\mathrm{CH}_2=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_3-\mathrm{CH}_3(\mathrm{~g})$
The heat of reaction is [bond energy of $\mathrm{C}-\mathrm{C}=80 \mathrm{kcal}, \mathrm{C}=\mathrm{C}=145 \mathrm{kcal}$,
$\mathrm{C}-\mathrm{H}=98 \mathrm{kcal}, \mathbf{H}-\mathrm{H}=103 \mathrm{kcal}]$

1 $-14 \mathrm{kcal}$
2 $-28 \mathrm{kcal}$
3 $-42 \mathrm{kcal}$
4 $-56 \mathrm{kcal}$
Thermodynamics

273038 The following reaction is performed at $298 \mathrm{~K}$ $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \to \mathrm{NO}_2(\mathrm{~g})$
The standard free energy of formation of $\mathrm{NO}(\mathrm{g})$ is $86.6 \mathrm{~kJ} / \mathrm{mol}$ at $298 \mathrm{~K}$. What is the standard free energy of formation of $\mathrm{NO}_2(g)$ at $298 \mathrm{~K} ?\left(\mathrm{~K}_{\mathrm{p}}=1.6 \times 10^{12}\right)$

1 $\mathrm{R}(298)$ In $\left(1.6 \times 10^{12}\right)-86600$
2 $86600+\mathrm{R}(298) \operatorname{In}\left(1.6 \times 10^{12}\right)$
3 $86600-\frac{\operatorname{In}\left(1.6 \times 10^{12}\right)}{\mathrm{R}(298)}$
4 $0.5\left[2 \times 86600-\mathrm{R}(298) \ln \left(1.6 \times 10^{12}\right)\right]$
Thermodynamics

273040 The standard enthalpy of formation of $\mathbf{N H}_3$ is $46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. If the enthalpy of formation of $\mathrm{H}_2$ from its atoms is $-436 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and that of $\mathrm{N}_2$ is $-712 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond enthalpy of $\mathrm{N}-\mathrm{H}$ bond in $\mathrm{NH}_3$ is

1 $-964 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $+352 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273030 The bond dissociation enthalpy of gaseous $\mathrm{H}_2$ $\mathrm{Cl}_2$ and $\mathrm{HCl}$ are 435,243 and $431 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{Y}}$ respectively. In the same unit, enthalpy of formation of $\mathrm{HCl}$ gas is

1 -92
2 -184
3 +92
4 +184
Thermodynamics

273031 The $\mathrm{H}-\mathrm{H}$ bond energy is $430 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\mathrm{Cl}$ $-\mathrm{Cl}$ bond energy is $240 \mathrm{~kJ} \mathrm{~mol}{ }^{-1}, \Delta \mathrm{H}$ for $\mathrm{HCl}$ is $-90 \mathrm{~kJ}$, The $\mathrm{H}-\mathrm{Cl}$ bond energy is about :

1 $180 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $360 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $213 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $425 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Thermodynamics

273032 $\mathrm{CH}_2=\mathrm{CH}_2(\mathrm{~g})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_3-\mathrm{CH}_3(\mathrm{~g})$
The heat of reaction is [bond energy of $\mathrm{C}-\mathrm{C}=80 \mathrm{kcal}, \mathrm{C}=\mathrm{C}=145 \mathrm{kcal}$,
$\mathrm{C}-\mathrm{H}=98 \mathrm{kcal}, \mathbf{H}-\mathrm{H}=103 \mathrm{kcal}]$

1 $-14 \mathrm{kcal}$
2 $-28 \mathrm{kcal}$
3 $-42 \mathrm{kcal}$
4 $-56 \mathrm{kcal}$
Thermodynamics

273038 The following reaction is performed at $298 \mathrm{~K}$ $2 \mathrm{NO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \to \mathrm{NO}_2(\mathrm{~g})$
The standard free energy of formation of $\mathrm{NO}(\mathrm{g})$ is $86.6 \mathrm{~kJ} / \mathrm{mol}$ at $298 \mathrm{~K}$. What is the standard free energy of formation of $\mathrm{NO}_2(g)$ at $298 \mathrm{~K} ?\left(\mathrm{~K}_{\mathrm{p}}=1.6 \times 10^{12}\right)$

1 $\mathrm{R}(298)$ In $\left(1.6 \times 10^{12}\right)-86600$
2 $86600+\mathrm{R}(298) \operatorname{In}\left(1.6 \times 10^{12}\right)$
3 $86600-\frac{\operatorname{In}\left(1.6 \times 10^{12}\right)}{\mathrm{R}(298)}$
4 $0.5\left[2 \times 86600-\mathrm{R}(298) \ln \left(1.6 \times 10^{12}\right)\right]$
Thermodynamics

273040 The standard enthalpy of formation of $\mathbf{N H}_3$ is $46.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$. If the enthalpy of formation of $\mathrm{H}_2$ from its atoms is $-436 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and that of $\mathrm{N}_2$ is $-712 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond enthalpy of $\mathrm{N}-\mathrm{H}$ bond in $\mathrm{NH}_3$ is

1 $-964 \mathrm{~kJ} \mathrm{~mol}^{-1}$
2 $+352 \mathrm{~kJ} \mathrm{~mol}^{-1}$
3 $+1056 \mathrm{~kJ} \mathrm{~mol}^{-1}$
4 $-1102 \mathrm{~kJ} \mathrm{~mol}^{-1}$