https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:calculating-the-equilibrium-constant/v/worked-examples-calculating-equilibrium-constants-from-equilibrium-concentrations-or-partial-pressures 2022-10-05T02:43:18.611402953Z Worked examples: Calculating equilibrium constants In this video, we'll calculate equilibrium constants using measurements of concentration and partial pressures at equilibrium. First, we'll find Kc for an equilibrium system using equilibrium concentrations. Then, we'll find Kp for a different system using equilibrium partial pressures. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/974389d9-063b-4465-8725-7a1dffa31ecd_1280_720_base.png Worked examples: Calculating equilibrium constants In this video, we'll calculate equilibrium constants using measurements of concentration and partial pressures at equilibrium. First, we'll find Kc for an equilibrium system using equilibrium concentrations. Then, we'll find Kp for a different system using equilibrium partial pressures. https://cdn.kastatic.org/ka-youtube-converted/5HZbCNg9mIw.mp4/5HZbCNg9mIw.mp4 492 Equilibrium https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:calculating-the-equilibrium-constant/e/calculating-the-equilibrium-constant 2025-05-23T18:26:12.433798667Z Calculating the equilibrium constant Practice calculations involving equilibrium constants in this set of free questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:using-the-reaction-quotient/v/using-the-reaction-quotient-ap 2022-10-05T02:43:18.611402953Z Using the reaction quotient By comparing the reaction quotient to the equilibrium constant, we can predict the direction a reaction will proceed to reach equilibrium. If Q < K, the reaction will proceed towards the products. If Q > K, the reaction will proceed towards the reactants. If Q = K, the reaction is already at equilibrium and will not change. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/a0771146-45eb-43c8-9971-8ee1ae530b23_1280_720_base.png Using the reaction quotient By comparing the reaction quotient to the equilibrium constant, we can predict the direction a reaction will proceed to reach equilibrium. If Q < K, the reaction will proceed towards the products. If Q > K, the reaction will proceed towards the reactants. If Q = K, the reaction is already at equilibrium and will not change. https://cdn.kastatic.org/ka-youtube-converted/JDUNQMj9Yk0.mp4/JDUNQMj9Yk0.mp4 470 Equilibrium https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:using-the-reaction-quotient/e/using-the-reaction-quotient 2025-02-05T10:28:14.374739025Z Using the reaction quotient Practice using the reaction quotient to predict the direction of a reaction in this set of free questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:calculating-equilibrium-concentrations/v/worked-example-calculating-equilibrium-concentrations-from-initial-concentrations-and-the-equilibrium-constant 2022-10-05T02:43:18.611402953Z Worked example: Calculating equilibrium concentrations from initial concentrations In this video, we'll learn how to use initial concentrations along with the equilibrium constant to calculate the concentrations of reaction species at equilibrium. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/fb51c53d-94e3-4809-b533-f6bda44d6378_1280_720_base.png Worked example: Calculating equilibrium concentrations from initial concentrations In this video, we'll learn how to use initial concentrations along with the equilibrium constant to calculate the concentrations of reaction species at equilibrium. https://cdn.kastatic.org/ka-youtube-converted/l81swfmUaek.mp4/l81swfmUaek.mp4 329 Equilibrium https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:calculating-equilibrium-concentrations/e/calculating-equilibrium-concentrations 2025-02-05T10:28:14.374739025Z Calculating equilibrium concentrations Practice finding concentrations or partial pressures at equilibrium in this set of free questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:le-chatelier-s-principle/v/le-chateliers-principle-changing-temperature 2022-09-05T08:18:59.810508578Z Le Chȃtelier’s principle: Changing temperature Le Chȃtelier’s principle can be used to predict the effect that a stress like changing temperature has on a system at equilibrium. If the temperature of the system is increased (at constant V), the system will shift in the direction that consumes the excess heat. If the temperature of the system is decreased, the reverse effect will be observed. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/ea29dc2b-8307-4daa-aad9-7010f1819348_1280_720_base.png Le Chȃtelier’s principle: Changing temperature Le Chȃtelier’s principle can be used to predict the effect that a stress like changing temperature has on a system at equilibrium. If the temperature of the system is increased (at constant V), the system will shift in the direction that consumes the excess heat. If the temperature of the system is decreased, the reverse effect will be observed. https://cdn.kastatic.org/ka-youtube-converted/j7FOzKIDrg8.mp4/j7FOzKIDrg8.mp4 676 Equilibrium https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:chemical-equilibrium/x203b0fc81a964b2d:le-chatelier-s-principle/e/using-le-chatelier-s-principle-exercise 2025-04-30T12:23:21.222584878Z Using Le Chatelier's principle Practice using Le Chatelier's principle to predict what happens to a reaction when a stress is applied Yuki exercise https://www.khanacademy.org/science/ka-chemistry-grade-11/x7b9df4d3282049b3:in-in-equilibrium/x7b9df4d3282049b3:in-in-factors-affecting-equilibria/e/le-chatlier-s-principle 2026-04-08T00:36:09.500768563Z Using Le Chatelier's Principle (part-2) Let's solve some problems to understand Le Chatlier's from first principles. Aanchal Arora exercise https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:acid-base-chemistry/x203b0fc81a964b2d:acid-base-theories/e/acids-and-bases 2021-04-29T07:52:16Z Definition of acids and bases Let's practice the questions which helps to learn the definition of acids and bases. Chaitra exercise https://www.khanacademy.org/science/odia-class-10-physical-sciences/x28e877d8a7566183:acids-bases-and-salts/x28e877d8a7566183:strength-of-acid-and-base/e/ph-and-ph-scale 2026-03-07T04:41:01.851344552Z Identify the nature of a substance based on pH (BASIC) Let's learn about pH and pH scale Chaitra exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:acids-and-bases/x2eef969c74e0d802:ph-and-poh-of-strong-acids-and-bases/e/ph-and-poh-of-strong-acids-and-bases 2025-02-05T10:28:14.374739025Z pH and pOH of strong acids and bases Practice calculations involving solutions of strong acids and bases in this set of free practice questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:acid-base-chemistry/x203b0fc81a964b2d:acid-base-theories/e/bronsted-lowry-concept-of-acids-and-bases 2025-02-05T10:28:14.374739025Z Bronsted-Lowry concept of acids and bases Exercise on understanding the Bronsted-Lowry concept of acids and bases exercise https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/copy-of-acid-base-equilibria/v/ph-of-salt-solutions 2021-01-04T18:35:18Z pH of salt solutions The pH of a salt solution is determined by the relative strength of its ​conjugated acid-base pair. Salts can be acidic, neutral, or basic. Salts that form from a strong acid and a weak base are acid salts, like ammonium chloride (NH4Cl). Salts that form from a weak acid and a strong base are basic salts, like sodium bicarbonate (NaHCO3). video https://cdn.kastatic.org/googleusercontent/T3Oa9Sm7mUVcyA4TjjZQ2zrfjfIPheerBPjAsuWUHjku1uze7xm30JzT1ZjnsACdeIouxX9x86zPTiGetMTSRTe1 pH of salt solutions The pH of a salt solution is determined by the relative strength of its ​conjugated acid-base pair. Salts can be acidic, neutral, or basic. Salts that form from a strong acid and a weak base are acid salts, like ammonium chloride (NH4Cl). Salts that form from a weak acid and a strong base are basic salts, like sodium bicarbonate (NaHCO3). https://cdn.kastatic.org/ka-youtube-converted/XZWoMXVANww.mp4/XZWoMXVANww.mp4 855 Equilibrium https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:acids-and-bases/x2eef969c74e0d802:weak-acid-and-base-equilibria/e/weak-acid-and-base-equilibria 2025-04-25T17:33:59.347925776Z Weak acid and base equilibria Practice calculations involving solutions of weak acids and bases in this set of free practice questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/ka-chemistry-grade-11/x7b9df4d3282049b3:in-in-equilibrium/x7b9df4d3282049b3:in-in-acid-base-equilibria/e/calculating-the-ph-of-salt-solutions 2025-02-05T10:28:14.374739025Z Calculating the pH of salt solutions Let's solve a few problems to calculate the pH of salts. Aanchal Arora exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:acids-and-bases/x2eef969c74e0d802:acidbase-reactions/v/worked-example-calculating-the-ph-after-a-weak-acid-strong-base-reaction-excess-acid 2022-10-05T02:43:18.611402953Z Worked example: Calculating the pH after a weak acid–strong base reaction (excess acid) When a strong base reacts with excess weak acid, the resulting solution contains both HA and A⁻. We can use reaction stoichiometry to determine the concentration of each species and then solve a common-ion equilibrium problem to find [H₃O⁺] and thus the pH. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/e5576b53-2b38-40f5-8df0-132dc7cf20a0_1280_720_base.png Worked example: Calculating the pH after a weak acid–strong base reaction (excess acid) When a strong base reacts with excess weak acid, the resulting solution contains both HA and A⁻. We can use reaction stoichiometry to determine the concentration of each species and then solve a common-ion equilibrium problem to find [H₃O⁺] and thus the pH. https://cdn.kastatic.org/ka-youtube-converted/9rRlLPx6w7M.mp4/9rRlLPx6w7M.mp4 544 Equilibrium https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:acids-and-bases/x2eef969c74e0d802:acidbase-reactions/e/acid-base-reactions 2025-02-05T10:28:14.374739025Z Acid–base reactions Check your understanding of acid–base reactions in this set of free practice questions designed for AP Chemistry students. exercise https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/buffer-solutions/v/buffer-solution-calculations 2021-01-04T18:35:19Z Buffer solution pH calculations Example of calculating the pH of a buffer solution using the Henderson-Hasselbalch equation, including the pH of the buffer solution after adding some NaOH.  video https://cdn.kastatic.org/googleusercontent/VuMnuOMsfszvfwrtCsD9U66RsNT0vyOQ2Dt5s3qhBsZngNR9lDX7V5_F28k-7bp9HFZTsX9um2ou5_z_PssctqU Buffer solution pH calculations Example of calculating the pH of a buffer solution using the Henderson-Hasselbalch equation, including the pH of the buffer solution after adding some NaOH.  https://cdn.kastatic.org/ka-youtube-converted/lsHq5aqz4uQ.mp4/lsHq5aqz4uQ.mp4 699 Equilibrium https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:acid-base-chemistry/x203b0fc81a964b2d:buffers-and-common-ion-effect/e/calculating-the-ph-of-buffer-solutions 2023-02-05T23:01:10.052992535Z Buffer solutions Let's solve a few problems to calculate the pH of a buffer solution. Aanchal Arora exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:solubility-equilibria/v/solubility-product-constant-from-the-solubility 2022-09-05T08:18:59.810508578Z Introduction to solubility equilibria The solubility product constant, Kₛₚ, is an equilibrium constant that reflects the extent to which an ionic compound dissolves in water. For compounds that dissolve to produce the same number of ions, we can directly compare their Kₛₚ values to determine their relative solubilities. If we know the solubility of a salt, we can use this information to calculate the Kₛₚ value for the compound. Jay video https://cdn.kastatic.org/ka_thumbnails_cache/72314172-3787-4009-a8d6-f99d45cb6b90_1280_720_base.png Introduction to solubility equilibria The solubility product constant, Kₛₚ, is an equilibrium constant that reflects the extent to which an ionic compound dissolves in water. For compounds that dissolve to produce the same number of ions, we can directly compare their Kₛₚ values to determine their relative solubilities. If we know the solubility of a salt, we can use this information to calculate the Kₛₚ value for the compound. https://cdn.kastatic.org/ka-youtube-converted/N9a2r01ToZk.mp4/N9a2r01ToZk.mp4 497 Equilibrium https://www.khanacademy.org/science/ka-chemistry-grade-11/x7b9df4d3282049b3:in-in-equilibrium/x7b9df4d3282049b3:in-in-solubility-equilibria-of-sparingly-soluble-salts/e/predicting-the-solubility-change-of-sparingly-soluble-salts-under-various-conditions 2025-02-05T10:28:14.374739025Z Predicting the solubility change of sparingly soluble salts under various conditions. Let's solve a few problems to understand how the solubility of a sparingly soluble salt changes when it's present under different conditions. Aanchal Arora exercise https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:equilibrium/x2eef969c74e0d802:solubility-equilibria/e/solubility-equilibria 2021-08-19T23:56:28.151270963Z Solubility equilibria Check your understanding of solubility equilibria in this set of free practice questions designed for AP Chemistry students. exercise