Thermodynamics Chapter Quiz

A process that happens naturally under a specific set of conditions.

A process that does not happen naturally under a specific set of conditions. It would require external intervention.

A measure of the disorder or randomness of a system. Higher entropy means greater disorder.

A thermodynamic state function that combines enthalpy (H) and entropy (S) to predict the spontaneity of a process. It is a measure of the maximum useful energy that can be obtained from a system.

The study of how different forms of energy are interconverted. It deals with the relationships between heat, work, temperature, and energy in physical and chemical processes.

A thermodynamic state function that describes the total energy of a system. It includes the internal energy of the system and the energy associated with the system's pressure and volume.

The energy change that occurs when 1 mole of a compound is formed from its constituent elements in their standard states.

The energy change that occurs during a chemical reaction under standard conditions (1 atm and 298 K).

The change in entropy of the universe for a process. It is the sum of the change in entropy of the system and the change in entropy of the surroundings.

The change in entropy of the system, which is typically a chemical reaction or a physical process.

The change in entropy of the surroundings, usually due to heat transfer between the system and the surroundings.

The change in entropy of the surroundings can be calculated by relating it to the enthalpy change of the system (ΔH) and the temperature (T).

The entropy of a perfect crystalline substance at absolute zero (0 Kelvin) is zero.

A change in entropy of the surroundings, calculated using the enthalpy change of the system and the temperature.

The entropy change of the surroundings is positive for exothermic processes, meaning the surroundings become more disordered as heat is released.

The entropy change of the surroundings is negative for endothermic processes, meaning the surroundings become more ordered as heat is absorbed.

The entropy change of the surroundings is inversely proportional to temperature. This means that at higher temperatures, the change in entropy of the surroundings is smaller.

The entropy change of the universe (ΔSuniverse) is the sum of the entropy changes of the system (ΔSsystem) and the surroundings (ΔSsurroundings).

A reaction is spontaneous if the entropy change of the universe is positive (ΔSuniverse > 0).

The Gibbs free energy change (ΔG) is a thermodynamic quantity that can be used to predict the spontaneity of a reaction. It is related to the enthalpy change (ΔH), the entropy change (ΔS), and the temperature (T) by the equation ΔG = ΔH - TΔS.

The spontaneity of a reaction can be determined by looking at the Gibbs free energy change (ΔG). If ΔG is negative, the reaction is spontaneous. If ΔG is positive, the reaction is non-spontaneous. If ΔG is zero, the reaction is at equilibrium.

The entropy of a substance in its standard state (298 K and 1 atm).

More complex structures have greater entropy because there are more ways for molecules to move and arrange themselves. For example, a molecule with more atoms and more bonds has greater entropy.

The more ordered form of a substance has lower entropy. For example, diamond is a very ordered structure, while graphite is less ordered.

The entropy of a liquid is greater than that of a solid because molecules in a liquid are more mobile and have more degrees of freedom.

The entropy of a gas is greater than that of a liquid because gas molecules are even more free to move and spread out.

The entropy of a system increases when the temperature increases because molecules have more energy and move more freely.

The entropy of the universe always increases for spontaneous processes. Energy tends to disperse and become more spread out.

The lowest point on a free energy diagram represents the point of equilibrium in a reaction, meaning the rates of the forward and reverse reactions are equal.

The change in Gibbs free energy (ΔG) represents the slope of the free energy diagram at any point along the reaction coordinate. A negative ΔG indicates the reaction will proceed spontaneously to achieve equilibrium.

The standard Gibbs free energy change (ΔG°) determines the position of equilibrium, indicated by the equilibrium constant (K). A large negative ΔG° suggests the equilibrium lies heavily on the product side, while a large positive ΔG° implies the equilibrium favors reactants.

The reaction coordinate represents the progress of a reaction from reactants to products, encompassing changes in molecular structure and energy. It's a theoretical measure of how far the reaction has proceeded.

A free energy diagram is a visual representation of how the Gibbs free energy of a reaction system changes as it progresses along the reaction coordinate, from reactants to products. It helps understand the thermodynamic favorability and equilibrium position of the reaction.

The standard free energy change of a reaction (ΔG°) is the change in Gibbs free energy when a reaction is carried out under standard conditions.

The standard free energy of formation (ΔG°f) is the change in Gibbs free energy when one mole of a compound is formed from its pure elements in their standard states.

It is the free energy change that occurs when one mole of the compound is formed from its constituent elements, each in their standard state. Therefore, ΔG°f = 0 for elements in their standard states.

The free energy change of a reaction at any temperature can be calculated from the standard free energy change and the standard entropy change.

The relationship between Gibbs free energy (ΔG) and standard free energy (ΔG°) is important for understanding the spontaneity of reactions.

The change in Gibbs free energy of a reaction can be used to predict whether the reaction is spontaneous (exergonic), non-spontaneous (endergonic), or at equilibrium. For a spontaneous reaction, ΔG < 0.

The standard free energy change of a reaction can be calculated from the standard free energies of formation of the reactants and products.

ΔG° is helpful to understand the overall spontaneity of a reaction under standard conditions, but ΔG helps predict the spontaneity in actual reactions.