(C) The formation reaction of ethane is: $2C_{\text{(graphite)}} + 3H_{2(g)} \rightarrow C_{2}H_{6(g)}$The enthalpy of formation is given by: $\Delta_

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(C) The formation reaction of ethane is: $2C_{\text{(graphite)}} + 3H_{2(g)} \rightarrow C_{2}H_{6(g)}$The enthalpy of formation is given by: $\Delta_{f}H^{\Theta}(C_{2}H_{6}) = [2 \times \Delta_{c}H^{\Theta}(C) + 3 \times \Delta_{c}H^{\Theta}(H_{2})] - \Delta_{c}H^{\Theta}(C_{2}H_{6})$Substituting the given values:$\Delta_{f}H^{\Theta}(C_{2}H_{6}) = [2 \times (-394.0) + 3 \times (-286.0)] - (-1560.0)$$\Delta_{f}H^{\Theta}(C_{2}H_{6}) = [-788.0 - 858.0] + 1560.0$$\Delta_{f}H^{\Theta}(C_{2}H_{6}) = -1646.0 + 1560.0 = -86.0 \ kJ \ mol^{-1}$

Class 11 Chemistry Thermodynamics Heat of reaction, Bond energy and Hess law

Medium

At $25^{\circ} C$ and $1 \ atm$ pressure,the enthalpies of combustion are as given below:

Substance $H_{2(g)}$ $C_{\text{(graphite)}}$ $C_{2}H_{6(g)}$

$\Delta_{c}H^{\Theta} / (kJ \ mol^{-1})$ $-286.0$ $-394.0$ $-1560.0$

The enthalpy of formation of ethane is ........ .

JEE MAIN 2022 All JEE MAIN

A
$+54.0 \ kJ \ mol^{-1}$
B
$-68.0 \ kJ \ mol^{-1}$
C
$-86.0 \ kJ \ mol^{-1}$
D
$+97.0 \ kJ \ mol^{-1}$

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Class 11

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Thermodynamics

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Heat of reaction, Bond energy and Hess law

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The enthalpy of combustion of carbon disulfide $(CS_2)$ is $-110.2 \, kJ \, mol^{-1}$. If the enthalpies of formation of $SO_2$ and $CO_2$ are $-297.4 \, kJ \, mol^{-1}$ and $-394.5 \, kJ \, mol^{-1}$ respectively,the enthalpy of formation of carbon disulfide is:

Medium

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$H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}$; $\Delta H$ at $298 \ K = -285.8 \ kJ$. The molar enthalpy of vaporization of water at $1 \ atm$ and $25^{\circ}C$ is $44 \ kJ$. The standard enthalpy of formation of $1 \ mole$ of water vapor at $25^{\circ}C$ is $...... \ kJ$. (in $.8$)

Medium

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Comment on the thermodynamic stability of $NO_{(g)}$,given:
$\frac{1}{2} N_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{(g)}; \Delta_r H^{\ominus} = 90 \, kJ \, mol^{-1}$
$NO_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{2(g)}; \Delta_r H^{\ominus} = -74 \, kJ \, mol^{-1}$

Easy

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The molar enthalpies of combustion of $C_2H_{2(g)},$ $C$ (graphite) and $H_{2(g)}$ are $-1300,$ $-394$ and $-286 \ kJ \ mol^{-1},$ respectively. The standard enthalpy of formation of $C_2H_{2(g)}$ is.......$kJ \ mol^{-1}$

Medium

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Given:
$2C + 2O_2 \to 2CO_2 : \Delta H = -787 \text{ kJ}$
$H_2 + \frac{1}{2}O_2 \to H_2O : \Delta H = -286 \text{ kJ}$
$C_2H_2 + \frac{5}{2}O_2 \to 2CO_2 + H_2O : \Delta H = -1310 \text{ kJ}$
Calculate the heat of formation of acetylene $(C_2H_2)$ in $\text{kJ}$.

Medium

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Substance	$H_{2(g)}$	$C_{\text{(graphite)}}$	$C_{2}H_{6(g)}$
$\Delta_{c}H^{\Theta} / (kJ \ mol^{-1})$	$-286.0$	$-394.0$	$-1560.0$

At $25^{\circ} C$ and $1 \ atm$ pressure,the enthalpies of combustion are as given below: Substance $H_{2(g)}$ $C_{\text{(graphite)}}$ $C_{2}H_{6(g)}$ $\Delta_{c}H^{\Theta} / (kJ \ mol^{-1})$ $-286.0$ $-394.0$ $-1560.0$ The enthalpy of formation of ethane is ........ .

Similar Questions

The enthalpy of combustion of carbon disulfide $(CS_2)$ is $-110.2 \, kJ \, mol^{-1}$. If the enthalpies of formation of $SO_2$ and $CO_2$ are $-297.4 \, kJ \, mol^{-1}$ and $-394.5 \, kJ \, mol^{-1}$ respectively,the enthalpy of formation of carbon disulfide is:

$H_{2(g)} + \frac{1}{2}O_{2(g)} \to H_2O_{(l)}$; $\Delta H$ at $298 \ K = -285.8 \ kJ$. The molar enthalpy of vaporization of water at $1 \ atm$ and $25^{\circ}C$ is $44 \ kJ$. The standard enthalpy of formation of $1 \ mole$ of water vapor at $25^{\circ}C$ is $...... \ kJ$. (in $.8$)

Comment on the thermodynamic stability of $NO_{(g)}$,given:$\frac{1}{2} N_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{(g)}; \Delta_r H^{\ominus} = 90 \, kJ \, mol^{-1}$$NO_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{2(g)}; \Delta_r H^{\ominus} = -74 \, kJ \, mol^{-1}$

The molar enthalpies of combustion of $C_2H_{2(g)},$ $C$ (graphite) and $H_{2(g)}$ are $-1300,$ $-394$ and $-286 \ kJ \ mol^{-1},$ respectively. The standard enthalpy of formation of $C_2H_{2(g)}$ is.......$kJ \ mol^{-1}$

Given: $2C + 2O_2 \to 2CO_2 : \Delta H = -787 \text{ kJ}$$H_2 + \frac{1}{2}O_2 \to H_2O : \Delta H = -286 \text{ kJ}$$C_2H_2 + \frac{5}{2}O_2 \to 2CO_2 + H_2O : \Delta H = -1310 \text{ kJ}$Calculate the heat of formation of acetylene $(C_2H_2)$ in $\text{kJ}$.

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At $25^{\circ} C$ and $1 \ atm$ pressure,the enthalpies of combustion are as given below:

Substance $H_{2(g)}$ $C_{\text{(graphite)}}$ $C_{2}H_{6(g)}$

$\Delta_{c}H^{\Theta} / (kJ \ mol^{-1})$ $-286.0$ $-394.0$ $-1560.0$

The enthalpy of formation of ethane is ........ .

Comment on the thermodynamic stability of $NO_{(g)}$,given:
$\frac{1}{2} N_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{(g)}; \Delta_r H^{\ominus} = 90 \, kJ \, mol^{-1}$
$NO_{(g)} + \frac{1}{2} O_{2(g)} \rightarrow NO_{2(g)}; \Delta_r H^{\ominus} = -74 \, kJ \, mol^{-1}$

Given:
$2C + 2O_2 \to 2CO_2 : \Delta H = -787 \text{ kJ}$
$H_2 + \frac{1}{2}O_2 \to H_2O : \Delta H = -286 \text{ kJ}$
$C_2H_2 + \frac{5}{2}O_2 \to 2CO_2 + H_2O : \Delta H = -1310 \text{ kJ}$
Calculate the heat of formation of acetylene $(C_2H_2)$ in $\text{kJ}$.