Entropy & Gibbs Free Energy

Front

What is Entropy?

Back

Entropy is a measure of the disorder or randomness in a system. It quantifies the amount of energy in a physical system that is not available to do work.

Front

What is Gibbs Free Energy?

Back

Gibbs Free Energy (G) is a thermodynamic potential that measures the maximum reversible work obtainable from a thermodynamic system at constant temperature and pressure.

Front

What is the relationship between Gibbs Free Energy and spontaneity?

Back

A reaction is spontaneous if the change in Gibbs Free Energy (ΔG) is negative (ΔG < 0).

Front

How does temperature affect spontaneity when both enthalpy and entropy are positive?

Back

When both enthalpy (ΔH) and entropy (ΔS) are positive, a high temperature is needed for the reaction to be spontaneous.

Front

What happens to entropy during a phase change from gas to solid?

Back

The entropy of the system decreases when a gas changes to a solid because the molecules become more ordered.

Front

What is the effect of increasing the number of moles of gas on entropy?

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Increasing the number of moles of gas generally increases the entropy of the system due to greater disorder.

Front

What is the significance of a negative enthalpy change?

Back

A negative enthalpy change (ΔH < 0) indicates that a reaction releases heat, making it exothermic.

Front

What type of temperature is required for a spontaneous reaction when both enthalpy and entropy are negative?

Back

A low temperature is required for a spontaneous reaction when both enthalpy and entropy are negative.

Front

What is the formula for Gibbs Free Energy?

Back

The formula for Gibbs Free Energy is ΔG = ΔH - TΔS, where ΔG is the change in Gibbs Free Energy, ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy.

Front

What does it mean if ΔG = 0?

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If ΔG = 0, the system is at equilibrium, and there is no net change in the concentrations of reactants and products.