For a particular reaction, Δ H ∘ = 20.1 kJ/mol and Δ S ∘ = 45.9 J / (mol ⋅ K). Assuming these values change very little with temperature,
at what temperature does the reaction change from nonspontaneous to spontaneous in the forward direction? T = K

Respuesta :

Answer: 438 K

Explanation:

According to Gibbs equation:

[tex]\Delta G=\Delta H-T\Delta S[/tex]

[tex]\Delta G[/tex] = Gibb's free energy change

[tex]\Delta H[/tex] = enthalpy change = 20.1 kJ/mol = 20100 J/mol

T = temperature

[tex]\Delta S[/tex] = entropy change = 45.9 J/Kmol

A reaction is at equilibrium when [tex]\Delta G[/tex] = Gibb's free energy change is zero and becomes spontaneous when [tex]\Delta G[/tex] = Gibb's free energy change is negative.

[tex]\Delta H=T\Delta S[/tex]

[tex]20100=T\times 45.9J/Kmol[/tex]

T=437.9K

Thus the temperature at which the reaction change from nonspontaneous to spontaneous in the forward direction is 438 K