Flashcard on Chemical Thermodynamics

Front

What is an open system in thermodynamics?

Back

An open system is one that can exchange both matter and energy with its surroundings.

Front

What is Gibbs Free Energy?

Back

Gibbs Free Energy (G) is the energy associated with a chemical reaction that can be used to do work at constant temperature and pressure. It relates enthalpy, temperature, and entropy.

Front

What characterizes an endothermic reaction?

Back

In an endothermic reaction, the system absorbs heat from the surroundings, resulting in a positive enthalpy change (ΔH > 0) and a negative temperature change (ΔT < 0).

Front

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

Back

A positive change in entropy (ΔS > 0) indicates that the reaction is spontaneous under the given conditions.

Front

What is the Second Law of Thermodynamics?

Back

The Second Law of Thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if all processes are reversible.

Front

Define enthalpy (H).

Back

Enthalpy (H) is a thermodynamic quantity that represents the total heat content of a system, defined as H = U + PV, where U is internal energy, P is pressure, and V is volume.

Front

What is the difference between exothermic and endothermic reactions?

Back

Exothermic reactions release heat to the surroundings (ΔH < 0), while endothermic reactions absorb heat from the surroundings (ΔH > 0).

Front

What is Hess's Law?

Back

Hess's Law states that the total enthalpy change for a reaction is the same, regardless of whether the reaction occurs in one step or multiple steps.

Front

What is calorimetry?

Back

Calorimetry is the measurement of heat transfer during chemical reactions or physical changes.

Front

What is the significance of the Gibbs Free Energy equation?

Back

The Gibbs Free Energy equation (ΔG = ΔH - TΔS) helps predict the spontaneity of a reaction: if ΔG < 0, the reaction is spontaneous; if ΔG > 0, it is non-spontaneous.