For the complete combustion of ethene,C_2H_{4 | vedclass

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(A) The combustion reaction is: $C_2H_{4(g)} + 3O_{2(g)} \rightarrow 2CO_{2(g)} + 2H_2O_{(l)}$.Given that the heat measured in a bomb calorimeter is t

Vedclass · Accepted Answer

$1411$

Vedclass · Answer

(A) The combustion reaction is: $C_2H_{4(g)} + 3O_{2(g)} ightarrow 2CO_{2(g)} + 2H_2O_{(l)}$.Given that the heat measured in a bomb calorimeter is the change in internal energy,$\Delta U = -1406 \ kJ \ mol^{-1}$.The change in the number of gaseous moles is $\Delta n_g = (2) - (1 + 3) = -2$.The relation between enthalpy change and internal energy change is $\Delta H = \Delta U + \Delta n_g RT$.Substituting the values: $\Delta H = -1406 \ kJ \ mol^{-1} + (-2 	imes 8.3 	imes 10^{-3} \ kJ \ K^{-1} \ mol^{-1} 	imes 300 \ K)$.$\Delta H = -1406 - 4.98 = -1410.98 \ kJ \ mol^{-1}$.At equilibrium,$\Delta G = 0$,which implies $\Delta H - T \Delta S = 0$,or $T \Delta S = \Delta H$.Therefore,$T \Delta S = -1410.98 \ kJ \ mol^{-1} \approx -1411 \ kJ \ mol^{-1}$.

Compound	$\Delta_f H^\circ$ $(kJ \ mol^{-1})$	$S^\circ$ $(J \ mol^{-1} \ K^{-1})$
$XY(g)$	$42$	$200$
$X_2(g)$	$8$	$140$
$Y_2(g)$	$80$	$250$

$(a)$ Entropy of vaporization	$(1)$ Decreases
$(b)$ $K$ for spontaneous process	$(2)$ Always has a $(+)$ value
$(c)$ Crystalline solid state	$(3)$ Has minimum entropy
$(d)$ $\Delta U$ for adiabatic expansion of an ideal gas	$(4)$ $\frac{\Delta H_{vap}}{T_b}$

Similar Questions

One mole of an ideal gas is allowed to expand reversibly and adiabatically from a temperature of $27\,^oC$. If the work done during the process is $3\,kJ$,the final temperature will be equal to $(C_v = 20\,J\,K^{-1} \, mol^{-1})$

Calculate the work done during the combustion of $0.138 \ kg$ of ethanol,$(C_2H_5OH_{(l)})$ at $300 \ K$. Given: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$ and molar mass of ethanol $= 46 \ g \ mol^{-1}$. (in $J$)

The value of $\Delta H_{transition}$ for $C(\text{graphite}) \rightarrow C(\text{diamond})$ is $1.9 \ kJ/mol$ at $25^{\circ}C$. The entropy of graphite is higher than the entropy of diamond. This implies that which of the following is incorrect $:-$

Match the following:

$(a)$ Entropy of vaporization $(1)$ Decreases

$(b)$ $K$ for spontaneous process $(2)$ Always has a $(+)$ value

$(c)$ Crystalline solid state $(3)$ Has minimum entropy

$(d)$ $\Delta U$ for adiabatic expansion of an ideal gas $(4)$ $\frac{\Delta H_{vap}}{T_b}$

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