https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:moles-and-molar-mass/v/the-mole-and-avogadro-s-number 2022-09-07T08:21:01.673602243Z The mole and Avogadro's number One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant. The concept of the mole can be used to convert between mass and number of particles. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/6088ce39-bf63-44b0-8918-4702d0c7bf46_1280_720_base.png The mole and Avogadro's number One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant. The concept of the mole can be used to convert between mass and number of particles. https://cdn.kastatic.org/ka-youtube-converted/cvi4IJMZ13Q.mp4/cvi4IJMZ13Q.mp4 537 The mole and the Avogadro constant https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/v/understanding-mole-concept-through-a-problem-pk 2025-12-31T05:23:06.848711158Z Understanding mole concept through a problem Let's understand what a mole is, why it's special and how we use the concept of a mole in numericals. Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Understanding mole concept through a problem Let's understand what a mole is, why it's special and how we use the concept of a mole in numericals. https://cdn.kastatic.org/ka-youtube-converted/eicrF9KRJ08.mp4/eicrF9KRJ08.mp4 448 The mole and the Avogadro constant https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:moles-and-molar-mass/v/calculations-using-avogadro-s-number-part-1 2024-08-16T15:18:47.217883837Z Calculations using Avogadro's number (part 1) Atomic mass units (a.m.u.) are much smaller than grams and are used to measure atomic-scale masses. Avogadro's number (6.022 x 10²³) represents the quantity of particles in one mole, linking atomic masses to measurable amounts in grams. Molar mass, expressed in grams per mole, bridges these concepts, enabling the conversion between the mass of a substance and the amount in moles. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/8e616a1d-8075-43b5-8623-d1e720cc3653_1280_720_base.png Calculations using Avogadro's number (part 1) Atomic mass units (a.m.u.) are much smaller than grams and are used to measure atomic-scale masses. Avogadro's number (6.022 x 10²³) represents the quantity of particles in one mole, linking atomic masses to measurable amounts in grams. Molar mass, expressed in grams per mole, bridges these concepts, enabling the conversion between the mass of a substance and the amount in moles. https://cdn.kastatic.org/ka-youtube-converted/umWiEZ-VpRM.mp4/umWiEZ-VpRM.mp4 811 The mole and the Avogadro constant https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:mole-calculations/v/calculations-using-avogadro-s-number-part-2 2024-09-09T20:45:32.418029564Z Calculations using Avogadro's number (part 2) Practice converting from grams to moles to molecules, formula units, and atoms through these four example problems. Grams are the standard unit of mass in the laboratory, while moles are used in calculations to relate mass to the number of particles. This system of units allows for communication between the microscopic world of atoms and the macroscopic world we interact with daily. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/46ccd225-0222-4c2c-829e-2dfb4ca10ee7_1280_720_base.png Calculations using Avogadro's number (part 2) Practice converting from grams to moles to molecules, formula units, and atoms through these four example problems. Grams are the standard unit of mass in the laboratory, while moles are used in calculations to relate mass to the number of particles. This system of units allows for communication between the microscopic world of atoms and the macroscopic world we interact with daily. https://cdn.kastatic.org/ka-youtube-converted/nC9i0zi1DCE.mp4/nC9i0zi1DCE.mp4 873 The mole and the Avogadro constant https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:moles-and-molar-mass/v/worked-example-calculating-molar-mass-and-number-of-moles 2022-09-07T08:21:01.673602243Z Worked example: Calculating molar mass and number of moles The molar mass of a substance is the mass in grams of 1 mole of the substance. As shown in this video, we can obtain a substance's molar mass by summing the molar masses of its component atoms. We can then use the calculated molar mass to convert between mass and number of moles of the substance. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/a85d2606-e7fa-4f30-be42-548a6905d16d_1280_720_base.png Worked example: Calculating molar mass and number of moles The molar mass of a substance is the mass in grams of 1 mole of the substance. As shown in this video, we can obtain a substance's molar mass by summing the molar masses of its component atoms. We can then use the calculated molar mass to convert between mass and number of moles of the substance. https://cdn.kastatic.org/ka-youtube-converted/PAqzpZ-nMlg.mp4/PAqzpZ-nMlg.mp4 349 The mole and the Avogadro constant https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:moles-and-molar-mass/e/understand-moles-and-molar-mass 2026-04-29T07:20:45.495372596Z Understand: Moles and molar mass Check your understanding of moles and molar mass in this set of free practice problems. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:mole-calculations/e/apply-mole-calculations-with-elements 2026-04-29T07:20:45.495372596Z Apply: Mole calculations with elements Apply your understanding of mole calculations with elements in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:mole-calculations/e/apply-mole-calculations-with-compounds 2026-04-29T07:20:45.495372596Z Apply: Mole calculations with compounds Apply your understanding of mole calculations with compounds in this set of free practice questions. Allen Ruch exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/v/avogadro-s-law 2025-12-18T18:40:53.641757593Z Avogadro's law Created by Khan Acadmey video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Avogadro's law Created by Khan Acadmey https://cdn.kastatic.org/ka-youtube-converted/6ABY8HToi-I.mp4/6ABY8HToi-I.mp4 477 The mole and the Avogadro constant https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/v/avogadros-law 2023-09-10T17:11:17.624018169Z Avogadro's law Explore Avogadro's Law with this engaging lesson. Discover how the Italian chemist Amedeo Avogadro's experiments with tiny particles led to the postulation that equal volumes of gas at the same temperature and pressure contain equal number of particles. This fundamental principle forms the basis of the ideal gas equation, a cornerstone in the study of physical processes. Ryan Scott Patton video https://cdn.kastatic.org/googleusercontent/rNdo_pZxKt5-_RaYFIRqAok8jFzQEILYDbzz1NWZv8lyemRRxYmPxTiC-r8WL5tfJVo-f_MNIzNHWgJHZ81N_JXr Avogadro's law Explore Avogadro's Law with this engaging lesson. Discover how the Italian chemist Amedeo Avogadro's experiments with tiny particles led to the postulation that equal volumes of gas at the same temperature and pressure contain equal number of particles. This fundamental principle forms the basis of the ideal gas equation, a cornerstone in the study of physical processes. https://cdn.kastatic.org/ka-youtube-converted/54--44LhQRU.mp4/54--44LhQRU.mp4 492 The mole and the Avogadro constant https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:solutions-acids-and-bases/x2613d8165d88df5e:molarity/v/molarity 2022-10-05T02:43:18.611402953Z Molarity The most common way to express solution concentration is molarity (M), which is defined as the amount of solute in moles divided by the volume of solution in liters: M = moles of solute/liters of solution. A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/6eb4fb56-c23e-43c9-a471-8d262eb601ae_1280_720_base.png Molarity The most common way to express solution concentration is molarity (M), which is defined as the amount of solute in moles divided by the volume of solution in liters: M = moles of solute/liters of solution. A solution that is 1.00 molar (written 1.00 M) contains 1.00 mole of solute for every liter of solution. https://cdn.kastatic.org/ka-youtube-converted/L-Uhyjt8t10.mp4/L-Uhyjt8t10.mp4 303 The mole and the Avogadro constant https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/a/molarity 2022-09-23T03:23:08.326640972Z Molarity Definitions of solution, solute, and solvent. How molarity is used to quantify the concentration of solute, and how to calculate molarity. article https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/e/apply-molarity-tx 2026-04-29T07:20:45.495372596Z Apply: molarity Apply your understanding of molarity in this set of free, standards-aligned practice questions. donna exercise https://www.khanacademy.org/science/cambridge-o-level-chemistry-cie/x8bc8fb44369617ed:stoichiometry/x8bc8fb44369617ed:the-mole-and-the-avogadro-constant/e/understand-molarity-tx 2026-04-07T23:36:17.218592739Z Understand: molarity Check your understanding of molarity in this set of free practice questions. donna exercise