Entropy and Gibbs Free Energy

Front

What is entropy (S)?

Back

Entropy is a measure of the disorder or randomness in a system. It quantifies the number of possible arrangements of particles in a system.

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What does a positive change in entropy (ΔS > 0) indicate?

Back

A positive change in entropy indicates that the disorder of the system has increased, often associated with processes like melting or vaporization.

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What does a negative change in entropy (ΔS < 0) indicate?

Back

A negative change in entropy indicates that the disorder of the system has decreased, often associated with processes like freezing or condensation.

Front

What is Gibbs Free Energy (G)?

Back

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

Front

What does a negative Gibbs Free Energy change (ΔG < 0) signify?

Back

A negative Gibbs Free Energy change signifies that a process is thermodynamically favorable and can occur spontaneously.

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What does a positive Gibbs Free Energy change (ΔG > 0) signify?

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A positive Gibbs Free Energy change signifies that a process is not thermodynamically favorable and will not occur spontaneously.

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What is the relationship between ΔG, ΔH, and ΔS?

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The relationship is given by the equation ΔG = ΔH - TΔS, where ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy.

Front

What conditions make a process thermodynamically favorable at all temperatures?

Back

A process is thermodynamically favorable at all temperatures if ΔS > 0 and ΔH < 0.

Front

What is the significance of the phase of a substance in terms of entropy?

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Gases have higher entropy than liquids, which have higher entropy than solids, due to the greater freedom of movement and arrangement of particles in gases.

Front

How does the dissolution of a solid in a solvent affect entropy?

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The dissolution of a solid in a solvent typically increases entropy (ΔS > 0) because the solid's ordered structure breaks down into more disordered ions or molecules.