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 is the formula for calculating Gibbs Free Energy?
ΔG = ΔH - TΔS, where ΔG is Gibbs Free Energy change, ΔH is Enthalpy change, T is Temperature (in Kelvin), and ΔS is Entropy change.
Describe the process of dissolving a substance in terms of enthalpy and entropy.
Energy is needed to break solute-solute and solvent-solvent attractions (endothermic, +ΔH). Forming new solute-solvent attractions releases energy (exothermic, -ΔH). Entropy usually increases as the solute becomes more dispersed in the solution (+ΔS).
How do you determine if the dissolution of a substance is spontaneous?
Calculate ΔG using the formula ΔG = ΔH - TΔS. If ΔG < 0, the dissolution is spontaneous. If ΔG > 0, the dissolution is non-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).