The standard heats of combustion of C_{(s)},S | vedclass

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Question

(C) The formation reaction for $CS_{2(\ell)}$ is: $C_{(s)} + 2S_{(s)} 	o CS_{2(\ell)}$The standard heat of formation $\Delta H_f^\circ$ is calculated

Vedclass · Accepted Answer

$+128.02$

Vedclass · Answer

(C) The formation reaction for $CS_{2(\ell)}$ is: $C_{(s)} + 2S_{(s)} 	o CS_{2(\ell)}$The standard heat of formation $\Delta H_f^\circ$ is calculated using the heats of combustion of reactants and products:$\Delta H_f^\circ = \sum \Delta H_c^\circ(	ext{reactants}) - \sum \Delta H_c^\circ(	ext{products})$$\Delta H_f^\circ = [\Delta H_c^\circ(C) + 2 	imes \Delta H_c^\circ(S)] - [\Delta H_c^\circ(CS_{2(\ell)})]$Substituting the given values:$\Delta H_f^\circ = [-393.3 + 2 	imes (-293.72)] - [-1108.76]$$\Delta H_f^\circ = [-393.3 - 587.44] + 1108.76$$\Delta H_f^\circ = -980.74 + 1108.76 = +128.02 \, kJ \, mol^{-1}$

$Cl_{2(g)} \rightarrow 2Cl_{(g)}$	$242.3 \ kJ \ mol^{-1}$
$I_{2(g)} \rightarrow 2I_{(g)}$	$151.0 \ kJ \ mol^{-1}$
$ICl_{(g)} \rightarrow I_{(g)} + Cl_{(g)}$	$211.3 \ kJ \ mol^{-1}$
$I_{2(s)} \rightarrow I_{2(g)}$	$62.76 \ kJ \ mol^{-1}$

The standard heats of combustion of $C_{(s)}$,$S_{(s)}$,and $CS_{2(\ell)}$ are $-393.3 \, kJ \, mol^{-1}$,$-293.72 \, kJ \, mol^{-1}$,and $-1108.76 \, kJ \, mol^{-1}$ respectively. The standard heat of formation of $CS_{2(\ell)}$ in $kJ \, mol^{-1}$ is:

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