Question

13 multiple choice 2 points the dehydrogenation of ethane (ch₃ - ch₃) to ethene (ch₂=ch₂) has δh° = +136 kj/mol and δs° = +120 j/kelvin - mol. calculate the value of δg° for the reaction at room temperature. is the reaction favored/ spontaneous or disfavored/non - spontaneous? δg° = +36 kj/mol the reaction is favored. δg° = +156 kj/mol the reaction is disfavored. δg° = +136 kj/mol the reaction is favored. δg° = +100 kj/mol the reaction is disfavored.

Explanation:

Step1: Convert temperature to Kelvin

Room - temperature $T = 298\ K$

Step2: Write the Gibbs - free energy formula

$\Delta G^{\circ}=\Delta H^{\circ}-T\Delta S^{\circ}$

Step3: Convert $\Delta S^{\circ}$ to $kJ/K\cdot mol$

$\Delta S^{\circ}=+ 120\ J/(K\cdot mol)=0.12\ kJ/(K\cdot mol)$

Step4: Substitute values into the formula

$\Delta G^{\circ}=136\ kJ/mol-298\ K\times0.12\ kJ/(K\cdot mol)$
$=136 - 35.76$
$=100.24\approx100\ kJ/mol$

Step5: Determine reaction spontaneity

Since $\Delta G^{\circ}>0$, the reaction is non - spontaneous (disfavored).

Answer:

D. $\Delta G^{\circ}= + 100\ kJ/mol$, The reaction is disfavored.