💾 Archived View for gem.sdf.org › s.kaplan › cheatsheets › subjects › science-and-technology › therm… captured on 2024-05-12 at 15:35:00.
⬅️ Previous capture (2023-09-28)
-=-=-=-=-=-=-
# Thermodynamics Cheatsheet ## Basic Concepts - **Thermodynamic System**: The region of the universe under study. - **Surroundings**: The rest of the universe. - **State Functions**: Properties that depend only on the current state of the system, not how it got there. Examples include internal energy (U), enthalpy (H), and entropy (S). - **Path Functions**: Properties that depend on the path taken to reach a certain state. Examples include work (W) and heat (Q). ## Laws of Thermodynamics 1. **First Law**: Energy cannot be created or destroyed, only transferred or converted from one form to another. Mathematically, this is expressed as `ΔU = Q - W`, where `ΔU` is the change in internal energy of the system, `Q` is the heat transferred to the system, and `W` is the work done by the system. 2. **Second Law**: The entropy of the universe tends to increase in any spontaneous process. Mathematically, this is expressed as `ΔS_universe = ΔS_system + ΔS_surroundings > 0`, where `ΔS_universe` is the change in entropy of the universe, `ΔS_system` is the change in entropy of the system, and `ΔS_surroundings` is the change in entropy of the surroundings. 3. **Third Law**: It is impossible to reach absolute zero (0 K) in a finite number of steps. ## Thermodynamic Processes - **Isothermal**: A process that occurs at constant temperature. - **Adiabatic**: A process that occurs without any heat exchange with the surroundings. - **Isobaric**: A process that occurs at constant pressure. - **Isochoric**: A process that occurs at constant volume. ## Enthalpy - **Enthalpy**: A state function that represents the heat content of a system. Mathematically, this is expressed as `H = U + PV`, where `H` is enthalpy, `U` is internal energy, `P` is pressure, and `V` is volume. - **Enthalpy Change**: The change in enthalpy of a system during a process. Mathematically, this is expressed as `ΔH = ΔU + PΔV`. ## Entropy - **Entropy**: A state function that represents the degree of disorder of a system. Mathematically, this is expressed as `ΔS = Q/T`, where `ΔS` is the change in entropy, `Q` is the heat transferred, and `T` is the temperature. - **Gibbs Free Energy**: A state function that combines enthalpy and entropy to predict the spontaneity of a process. Mathematically, this is expressed as `ΔG = ΔH - TΔS`. ## Resources - [MIT OpenCourseWare: Thermodynamics & Kinetics](https://ocw.mit.edu/courses/chemistry/5-60-thermodynamics-kinetics-spring-2008/) - [Khan Academy: Thermodynamics](https://www.khanacademy.org/science/physics/thermodynamics) - [Chemguide: Thermodynamics](https://www.chemguide.co.uk/physical/basicrates/thermodynamics.html)