All Flashcards
What is the definition of entropy (ΔS)?
A measure of disorder or randomness in a system; the number of possible arrangements.
What is the definition of Gibbs Free Energy (ΔG)?
A thermodynamic potential that measures the amount of energy available in a chemical or physical system to do useful work at a constant temperature and pressure.
What does a negative ΔG indicate?
A spontaneous (thermodynamically favorable) reaction.
What does a positive ΔG indicate?
A nonspontaneous (thermodynamically unfavorable) reaction.
Define enthalpy (ΔH).
A measure of the heat energy released or absorbed during a chemical reaction.
What does it mean for a reaction to be thermodynamically favorable?
The reaction will proceed forward without needing additional energy input (spontaneous).
What are the differences between enthalpy and entropy?
Enthalpy (ΔH): Measures heat transfer in a reaction (exothermic or endothermic). Entropy (ΔS): Measures the disorder or randomness of a system.
Compare spontaneous and non-spontaneous reactions in terms of Gibbs Free Energy and the equilibrium constant (K).
Spontaneous: ΔG < 0, K > 1 (favors products). Non-spontaneous: ΔG > 0, K < 1 (favors reactants).
What is the effect of increasing temperature on the spontaneity of an endothermic reaction with a positive ΔS?
Increasing temperature makes the reaction more likely to be spontaneous (more negative ΔG).
What is the effect of a large positive ΔH on the solubility of a substance?
A large positive ΔH makes the substance less likely to dissolve spontaneously, especially at lower temperatures.
What is the effect of a large positive ΔS on the solubility of a substance?
A large positive ΔS makes the substance more likely to dissolve spontaneously, especially at higher temperatures.
What happens to entropy during a phase change from solid to gas?
Entropy increases because the molecules have more freedom to move around, leading to greater disorder.
What happens if ΔG = 0?
The reaction is at equilibrium.