Study "Thermochemistry and Thermodynamics", a flashcard deck on FORKSAI.
What is defined as the 'system' in thermochemistry?
The system is the specific set of substances and energy (e.g., a chemical reaction) that is being studied or observed.
What constitutes the 'surroundings' in thermochemistry?
The surroundings include everything that is not directly involved with the system or reaction being studied.
In a chemical reaction, which component is typically considered the 'system'?
In chemistry, the reaction itself (reactants and products, and their associated energy) is the primary system of interest.
State the First Law of Thermodynamics.
The First Law of Thermodynamics, also known as the Law of Conservation of Energy, states that the total energy of an isolated system remains constant; energy cannot be created or destroyed, only converted from one form into another.
What is the mathematical expression for the First Law of Thermodynamics, and what do its terms represent?
The expression is ΔU = Q - W, where: - ΔU (or ΔE) is the change in internal energy of the system. - Q is the heat transferred to or from the system. - W is the work done by or on the system.
State the Second Law of Thermodynamics.
The Second Law of Thermodynamics states that any spontaneous process must lead to an increase in the total entropy of the universe (ΔS_universe > 0).
How is the Second Law of Thermodynamics conceptually linked to the spontaneity of a process?
It implies that for a process to be spontaneous, the overall disorder or randomness of the universe (system + surroundings) must increase.
Which thermodynamic state function is often used to predict spontaneity based on the Second Law, especially at constant temperature and pressure?
Gibbs Free Energy (ΔG) is used to predict spontaneity, as it combines enthalpy and entropy changes of the system to reflect the overall entropy change of the universe.
Define a thermodynamic state function.
A thermodynamic state function is a property of a system that depends only on the current state of the system, not on the path taken to reach that state. Examples include internal energy, enthalpy, entropy, and Gibbs free energy.
What is Internal Energy (ΔU or ΔE)?
Internal energy is the total energy of a system, comprising the potential vibrational energy of atoms and the kinetic energy of molecules within the system.