https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:applications-of-thermodynamics/x2eef969c74e0d802:entropy/v/introduction-to-entropy-ap 2022-10-05T02:43:18.611402953Z Introduction to entropy According to the Boltzmann equation, entropy is a measure of the number of microstates available to a system. The number of available microstates increases when matter becomes more dispersed, such as when a liquid changes into a gas or when a gas is expanded at constant temperature. It also increases when energy becomes more dispersed, which occurs with an increase in temperature. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/6db2754b-3a87-4e64-b8f2-35417abdb1e0_1280_720_base.png Introduction to entropy According to the Boltzmann equation, entropy is a measure of the number of microstates available to a system. The number of available microstates increases when matter becomes more dispersed, such as when a liquid changes into a gas or when a gas is expanded at constant temperature. It also increases when energy becomes more dispersed, which occurs with an increase in temperature. https://cdn.kastatic.org/ka-youtube-converted/0Z2bIv4DXts.mp4/0Z2bIv4DXts.mp4 714 Entropy https://www.khanacademy.org/science/biology/energy-and-enzymes/the-laws-of-thermodynamics/v/introduction-to-entropy 2021-10-06T19:08:53.089656177Z Introduction to entropy Introduction to entropy, and how entropy relates to the number of possible states for a system. video https://cdn.kastatic.org/googleusercontent/T6WXdV7LynXhhaIjNssG7ANT6yLOJpLwDKkyxIwi3tofD46b47esmMOau0loXGTfMVASTyoGklDvR5BULPDzwOPm Introduction to entropy Introduction to entropy, and how entropy relates to the number of possible states for a system. https://cdn.kastatic.org/ka-youtube-converted/Svvr5uF_FZ8.mp4/Svvr5uF_FZ8.mp4 447 Entropy https://www.khanacademy.org/science/ap-biology/cellular-energetics/cellular-energy/v/second-law-of-thermodynamics-and-entropy 2023-05-02T21:08:26.186654054Z Second Law of Thermodynamics and entropy Entropy is a measure of disorder or randomness in a system. It represents the number of possible states or configurations that a system can take on. According to the Second Law of Thermodynamics, entropy tends to increase over time, meaning that systems naturally progress towards a more disordered or random state. video https://cdn.kastatic.org/googleusercontent/ppieV8AlxHEaQH6o-oTIgZmW6ODor107nEd5kVzcWU0Fw-gmgRG5BnHn65VJgVSO551-BqD2KXLIAMkRviyDwzE Second Law of Thermodynamics and entropy Entropy is a measure of disorder or randomness in a system. It represents the number of possible states or configurations that a system can take on. According to the Second Law of Thermodynamics, entropy tends to increase over time, meaning that systems naturally progress towards a more disordered or random state. https://cdn.kastatic.org/ka-youtube-converted/axG9HuqViDY.mp4/axG9HuqViDY.mp4 512 Entropy https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:applications-of-thermodynamics/x2eef969c74e0d802:entropy/v/absolute-entropy-and-entropy-change 2022-10-05T02:43:18.611402953Z Absolute entropy and entropy change The standard molar entropy of a substance is the absolute entropy of 1 mole of the substance in the standard state. For any chemical reaction, the standard entropy change is the sum of the standard molar entropies of the products minus the sum of the standard molar entropies of the reactants. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/2ccb4e70-a7f3-421f-b344-da0b30119767_1280_720_base.png Absolute entropy and entropy change The standard molar entropy of a substance is the absolute entropy of 1 mole of the substance in the standard state. For any chemical reaction, the standard entropy change is the sum of the standard molar entropies of the products minus the sum of the standard molar entropies of the reactants. https://cdn.kastatic.org/ka-youtube-converted/ObridY7EHyk.mp4/ObridY7EHyk.mp4 688 Entropy https://www.khanacademy.org/science/grade-11-physics-snc-aligned/x1d0fed5276339e80:heat-and-thermodynamics/x1d0fed5276339e80:entropy-and-the-disorder-of-energy-in-natural-processes/e/gibb-s-free-energy-and-entropy 2025-05-14T05:31:01.421518925Z Entropy changes (Basic) Let's solve a few problems to calculate the understand what process decrease or increase entropy and how! Aanchal Arora exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:applications-of-thermodynamics/x2eef969c74e0d802:entropy/e/entropy 2026-03-11T21:40:48.828994006Z Entropy Check your understanding of entropy changes in physical and chemical processes in this set of free practice questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:chemical-energetics/x203b0fc81a964b2d:entropy/v/gibbs-free-energy-and-spontaneity 2021-01-04T18:35:20Z Gibbs free energy and spontaneity Intuition behind why spontaneity is driven by enthalpy, entropy and temperature. Introduction to Gibbs free energy. Sal Khan video https://cdn.kastatic.org/googleusercontent/udX74k_5Xp3MUMeNrWfsOlAhjTmxr-YFKaON5KPzy5NnN-8WW9E2NSsRFRjjkNqnUEI-HqmrsiPpO-Q6BtYqA0hB Gibbs free energy and spontaneity Intuition behind why spontaneity is driven by enthalpy, entropy and temperature. Introduction to Gibbs free energy. https://cdn.kastatic.org/ka-youtube-converted/ViAmQivKif0.mp4/ViAmQivKif0.mp4 1060 Entropy https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:chemical-energetics/x203b0fc81a964b2d:entropy/v/gibbs-free-energy-example 2021-01-04T18:35:18Z Gibbs free energy example Determining if a reaction is spontaneous by calculating the change in Gibbs free energy. Also calculates the change in entropy using table of standard entropies.  Sal Khan video https://cdn.kastatic.org/googleusercontent/VOArlCkkxRX7NoWV8Eb6iaqIzIuhX9Uo8iut4Q3E2XkFr1Z_bqPdhWCXEI89go5MrNwBzRlmZn80pETpSrdt6glI Gibbs free energy example Determining if a reaction is spontaneous by calculating the change in Gibbs free energy. Also calculates the change in entropy using table of standard entropies.  https://cdn.kastatic.org/ka-youtube-converted/sG1ZAdYi13A.mp4/sG1ZAdYi13A.mp4 597 Entropy https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:chemical-energetics/x203b0fc81a964b2d:entropy/a/gibbs-free-energy-and-spontaneity 2021-04-29T08:01:43Z Gibbs free energy and spontaneity How the second law of thermodynamics helps us determine whether a process will be spontaneous, and using changes in Gibbs free energy to predict whether a reaction will be spontaneous in the forward or reverse direction (or whether it is at equilibrium!).  article