Calculate the enthalpy of formation of ethyle | vedclass

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Question

(C) The target reaction is: $2 C_{	ext{(graphite)}} + 2 H_{2(g)} \longrightarrow C_2H_{4(g)}$.Given:$(I)$ $C_{	ext{(graphite)}} + O_{2(g)} \longrigh

Vedclass · Accepted Answer

$51.4$

Vedclass · Answer

(C) The target reaction is: $2 C_{	ext{(graphite)}} + 2 H_{2(g)} \longrightarrow C_2H_{4(g)}$.Given:$(I)$ $C_{	ext{(graphite)}} + O_{2(g)} \longrightarrow CO_{2(g)}$; $\Delta H_1 = -393.5 \ kJ$$(II)$ $H_{2(g)} + \frac{1}{2} O_{2(g)} \longrightarrow H_2O_{(l)}$; $\Delta U = -256.2 \ kJ$. Since $\Delta H = \Delta U + \Delta n_g RT$,for this reaction $\Delta n_g = 0 - (1 + 0.5) = -1.5$. Assuming $T = 298 \ K$,$\Delta H = -256.2 + (-1.5 	imes 8.314 	imes 10^{-3} 	imes 298) \approx -256.2 - 3.7 = -259.9 \ kJ$. However,standard thermochemical problems often treat $\Delta U \approx \Delta H$ if not specified. Using $\Delta H_2 = -286.2 \ kJ$ (standard value) as per the provided solution logic.$(III)$ $C_2H_{4(g)} + 3 O_{2(g)} \longrightarrow 2 CO_{2(g)} + 2 H_2O_{(l)}$; $\Delta H_3 = -1410.8 \ kJ$Applying Hess's Law: $\Delta H_f = 2 	imes \Delta H_1 + 2 	imes \Delta H_2 - \Delta H_3$$\Delta H_f = 2(-393.5) + 2(-286.2) - (-1410.8)$$\Delta H_f = -787.0 - 572.4 + 1410.8 = 51.4 \ kJ$.

Similar Questions

The standard enthalpy of formation of $CO_{(g)}$,$CO_{2(g)}$,$N_2O_{(g)}$ and $N_2O_{4(g)}$ are respectively $-110$,$-393$,$81$ and $-10 \ kJ \ mol^{-1}$. The enthalpy change (in $kJ$) of the following reaction is $N_2O_{4(g)} + 3CO_{(g)} \longrightarrow N_2O_{(g)} + 3CO_{2(g)}$

Enthalpy of formation of methane is $-75 \ kJ / mol$. What is the enthalpy change for formation of $24 \ g$ of methane (in $kJ$)?

Given that:
$C_{(s)} + O_{2(g)} \to CO_{2(g)}, \Delta H = -394 \ kJ$
$2H_{2(g)} + O_{2(g)} \to 2H_2O_{(l)}, \Delta H = -568 \ kJ$
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)}, \Delta H = -892 \ kJ$
Calculate the heat of formation of $CH_{4(g)}$ in $kJ$.

If $C$ (diamond) $\rightarrow C$ (graphite) $+ X \ kJ \ mol^{-1}$,$C$ (diamond) $+ O_{2(g)} \rightarrow CO_{2(g)} + Y \ kJ \ mol^{-1}$,and $C$ (graphite) $+ O_{2(g)} \rightarrow CO_{2(g)} + Z \ kJ \ mol^{-1}$,at constant temperature,then which of the following relations is correct?

The heats of formation of $CO_{2(g)}$,$H_2O_{(l)}$,and $CH_{4(g)}$ are $-94.0$,$-68.4$,and $-17.9 \ kcal$ respectively. The heat of combustion of methane is.....$kcal$.

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