https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:atoms-isotopes-and-ions/x2613d8165d88df5e:isotopes-and-ions/v/average-atomic-mass 2022-07-29T13:48:23.370439724Z Average atomic mass The average atomic mass (sometimes called atomic weight) of an element is the weighted average mass of the atoms in a naturally occurring sample of the element. Average masses are generally expressed in unified atomic mass units (u), where 1 u is equal to exactly one-twelfth the mass of a neutral atom of carbon-12. Sal Khan video https://cdn.kastatic.org/googleusercontent/1rWF_Sm-ov4z3_Tm3RojlNxBlONAGoAJE-b9W7zP9blvbt1VpVl3g7vXDYrT6ccW1nQG9pZLgV6kp-R-tibaw5XudchkKh6hQZ6y Average atomic mass The average atomic mass (sometimes called atomic weight) of an element is the weighted average mass of the atoms in a naturally occurring sample of the element. Average masses are generally expressed in unified atomic mass units (u), where 1 u is equal to exactly one-twelfth the mass of a neutral atom of carbon-12. https://cdn.kastatic.org/ka-youtube-converted/YsqoF3hqdkg.mp4/YsqoF3hqdkg.mp4 518 Concept of mole 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 Concept of mole https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:stoichiometry/x203b0fc81a964b2d:concept-of-mole/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 Concept of mole 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 Concept of mole https://www.khanacademy.org/science/ap-chemistry-beta/x2eef969c74e0d802:atomic-structure-and-properties/x2eef969c74e0d802:moles-and-molar-mass/e/moles-and-molar-mass 2025-04-25T18:12:38.199351774Z Moles and molar mass Practice converting between moles, mass, and number of particles in this set of free questions designed for AP Chemistry students. Lauren Rosebrugh exercise https://www.khanacademy.org/science/grade-11-chemistry-snc-aligned/x203b0fc81a964b2d:stoichiometry/x203b0fc81a964b2d:concept-of-mole/e/number-of-atoms-moles-and-molar-mass 2025-02-05T10:28:14.374739025Z Number of atoms, moles and molar mass Through this exercise, we will further our understanding of the mole concept, molar mass and how to find out constituent entities in a substance (atoms, molecules, ions) using molar mass. Revathi exercise https://www.khanacademy.org/science/hs-chemistry/x2613d8165d88df5e:stoichiometry-and-the-mole/x2613d8165d88df5e:moles-and-molar-mass/e/understand-moles-and-molar-mass 2026-03-26T05:30:45.387289448Z Understand: moles and molar mass Check your understanding of moles and molar mass in this set of free practice problems. Allen Ruch exercise