Atomic Mass Unit, Atomic Mass

[@ShukokaiStu]

Richard this is great, thank you very much for these fantastic videos.

[@aashipriya6694]

You're absolutely amazing.. 1 question what about tin?! It has more than 20 isotopes so for tin's amu do the scientists have calculated all 50 isotopes's amu?

[@richardlouiechemistrylectures]

There are 10 stable isotopes of tin and 29 radioactive isotopes. The average atomic mass is calculated from the naturally occurring isotopes. So my guess is that the average atomic mass is calculated from the 10 stable isotopes. If any of the radioactive isotopes occur naturally, they would be included in the calculation.

[@aashipriya6694]

@@richardlouiechemistrylectures thank you so much!💫

[@aashipriya6694]

@@richardlouiechemistrylectures how will anyone find lithium 6 or 7 or any others amu!? In this video we are just calculating average amu! I am really confused and curious! Like how, Carbon 12 amu was found? Using a sensitive weighing machine or else thing? Please help me out 🥺

[@richardlouiechemistrylectures]

The trick to measuring the mass of isotopes is that you first grind up a sample of the element (say lithium) and heat it until it turns into a gas. Then you shoot the gas out of a tube and catch the gas when it falls a certain distance from the tube. The lighter isotopes will travel further and the heavier isotopes won't travel as far. The distance the isotope lands from the tube correlates to its mass, and that's how you get the mass of the individual isotope. So the lithium 6 isotope would travel further than the lithium 7 isotope.

[@aashipriya6694]

@@richardlouiechemistrylectures thank you sooooo much... You really are amazing. Surely gonna sub u!😭💗

[@smizzye8546]

Thanks for the lesson. I'm taking this for physics

[@randomuser2461]

If only there was someplace that displayed all this convenient information in one condensed place so we could see it all at once. Someone should invent such a thing. Charts are so lacking.

[@manuelcastaneda1888]

amu = 1.66054 ×10^-27 kg