Thermodynamics: Gibbs Free Energy and Spontaneity

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What happens to the availability of useful energy in a system when it becomes more disordered?

More useful energy becomes available to do work.

What is the direction of a reaction when ΔG is negative?

The reaction is spontaneous in the forward direction.

What is the primary difference between Gibbs free energy and enthalpy?

Gibbs free energy is the amount of 'free' or 'available' energy a system possesses to do work, whereas enthalpy is the total energy of a system.

What is the condition for a reaction to be at equilibrium?

ΔG is zero. Signup and view all the answers

What is the preferred condition for spontaneous reactions in terms of ΔH and ΔS?

A negative ΔH and a positive ΔS. Signup and view all the answers

How does the sign of ΔG° relate to the spontaneity of a reaction?

A negative ΔG° indicates a spontaneous reaction, while a positive ΔG° indicates a non-spontaneous reaction. Signup and view all the answers

What is the role of entropy in determining the spontaneity of a reaction?

Entropy (ΔS) helps to determine the spontaneity of a reaction by indicating the change in disorder or randomness of the system. Signup and view all the answers

What is the relationship between ΔG and Keqm?

ΔG = -RTlnK Signup and view all the answers

How does the Gibbs equation relate to the equilibrium constant (Keq)?

ΔG° = -RTln(Keq), where R is the gas constant and T is the temperature in Kelvin. Signup and view all the answers

What does a Keqm value greater than 1 indicate?

Products are favoured. Signup and view all the answers

What is the significance of the Kelvin temperature (T) in the Gibbs equation?

The Kelvin temperature (T) is used to scale the entropy term (ΔS) in the Gibbs equation, allowing for the calculation of ΔG° at a specific temperature. Signup and view all the answers

Using the given data, is the reaction H2O(l) → H2O(g) spontaneous at room temperature?

No, the reaction is not spontaneous at room temperature, as ΔG° = ΔH° - TΔS° = -286 kJ/mol - (298 K)(0.070 J/K·mol) = 34 kJ/mol, which is positive. Signup and view all the answers