https://www.khanacademy.org/science/class-9-chemistry/x46dd29ce84a663ea:is-matter-around-us-pure/x46dd29ce84a663ea:difference-between-pure-substances-and-mixtures/v/pure-substances-and-mixtures 2023-06-26T12:36:08.867767149Z Pure substances and Mixtures What is the difference between helium and air? Or iron and salt water? Let's find out! Vibhor Pandey video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Pure substances and Mixtures What is the difference between helium and air? Or iron and salt water? Let's find out! https://cdn.kastatic.org/ka-youtube-converted/r076_Q0xi60.mp4/r076_Q0xi60.mp4 1046 Elements https://www.khanacademy.org/science/class-9-chemistry/x46dd29ce84a663ea:is-matter-around-us-pure/x46dd29ce84a663ea:difference-between-pure-substances-and-mixtures/e/pure-substances-and-mixtures 2026-05-05T06:20:51.172698853Z Pure substances and mixtures Let's solve a few problems to understand the difference between pure substances and mixtures. Aanchal Arora exercise https://www.khanacademy.org/science/ap-biology/chemistry-of-life/elements-of-life/v/elements-and-atoms 2023-03-31T23:16:47.953017837Z Elements and atoms Elements are pure substances with specific properties. Atoms are the smallest units of elements that still retain the element's properties. Atoms contain electrons, neutrons, and protons. Each element is defined by the number of protons in its nucleus. Sal Khan video https://cdn.kastatic.org/googleusercontent/zfLHeNHjPfEhSYfKtZLu6Ft_uFg2p_L9gALjUyfahbjdBzZbrDLxrg-rk_mrsUBBVIKs44ALBBI1Gv8cm2O_Ppa05g Elements and atoms Elements are pure substances with specific properties. Atoms are the smallest units of elements that still retain the element's properties. Atoms contain electrons, neutrons, and protons. Each element is defined by the number of protons in its nucleus. https://cdn.kastatic.org/ka-youtube-converted/IFKnq9QM6_A.mp4/IFKnq9QM6_A.mp4 789 Elements https://www.khanacademy.org/science/up-science-grade-6-revision-course-full-term/x017c12e57b64cfa8:week-1/x017c12e57b64cfa8:untitled-210/e/elements-compounds-and-mixtures-in 2026-06-15T04:30:38.969568377Z Elements, Compounds and mixtures Let's solve some questions on elements, compounds and mixtures Vibhor Pandey exercise