Thermodynamics and Reaction Principles

These flashcards cover key concepts, definitions, and equations from the lecture material on thermodynamics, reaction principles, and concepts related to energy, entropy, and spontaneity.

What is a spontaneous process in thermodynamics?

A process that occurs without needing to be driven by an external force.

What does the first law of thermodynamics state?

Energy cannot be created or destroyed, only changed from one form to another.

What happens during isothermal expansion of a gas?

The temperature stays constant and the gas expands, requiring work done to be equal to the heat added.

In an isothermal process, what is the relationship between heat (q), work (w), and change in internal energy (ΔE)?

ΔE = 0, thus q = -w.

What equation would you use to calculate the work done during an isothermal expansion?

W = -nRT ln(Vf/Vi) where Vf and Vi are the final and initial volumes.

What is the definition of entropy in the context of thermodynamics?

Entropy (S) is a measure of the disorder of a system and can be calculated as ΔS = q_rev/T.

How does the second law of thermodynamics relate entropy to spontaneity?

It states that the total entropy of the universe increases for spontaneous processes.

What is the relationship between free energy (G), enthalpy (H), and entropy (S)?

G = H - TS, where T is absolute temperature.

What does a negative free energy change (ΔG) indicate about a process?

It indicates that the process is spontaneous.

How does temperature affect the spontaneity of reactions with positive ΔS and negative ΔH?

Such reactions are spontaneous at all temperatures.

What is the significance of microstates in thermodynamics?

Microstates represent the different ways a system can be arranged at a molecular level, affecting its entropy.

What is the Gibbs free energy change (ΔG) for ATP hydrolysis?

The standard Gibbs free energy change (ΔG°) for ATP hydrolysis is approximately -30.5 kJ/mol.

What is the effect of a greater number of moles of products versus reactants on entropy?

More moles of products generally lead to greater entropy, resulting in a positive ΔS.

Define the term 'ideal gas' in the context of thermodynamics.

An ideal gas is a theoretical gas that follows the ideal gas law (PV=nRT) perfectly, with no interactions between molecules.

What is the main conclusion of the Van’t Hoff equation?

It relates the change in the equilibrium constant (K) of a reaction to the change in temperature, providing a quantitative measure of the effects of temperature on the equilibrium state.