this post was submitted on 12 Dec 2023
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246
freedom units be like (lemmy.world)
submitted 8 months ago by [email protected] to c/[email protected]
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[–] [email protected] 53 points 8 months ago (3 children)

Atomic mass is measured in u, not atoms. That would be moles.

[–] [email protected] 18 points 8 months ago (2 children)

And measuring in moles is way less crazy than measuring in eagles.

[–] [email protected] 10 points 8 months ago (1 children)

Really? Now I have to go dig up some moles…

Which, ah, species is best here?

[–] [email protected] 13 points 8 months ago

Guaca

[–] [email protected] 3 points 8 months ago

I am a mole and I live in a hole!

[–] [email protected] 7 points 8 months ago (2 children)

Im debating with myself whether moles are truly a units because unlike other units moles are just a conveniently large amount but unlike other units moles could fully be replaced by a factor

[–] [email protected] 7 points 8 months ago

Yeah they aren't a unit in the sense that they make a non-quantifiable measure quantifiable. In dimensional analysis they would have the dimension [1]. But they can still be regarded as a unit since they act in the exact same way, just like other factors do. But yeah, they are more akin to the SI prefixes like kilo, or something like a dozen or a gross.

[–] [email protected] 3 points 8 months ago* (last edited 8 months ago) (1 children)

A mole isn't just convenient. I'm sure there's a youtube somewhere that explains it but advagadros number is a product of the fact that: 1) every atom of an element has a weight (or at least an average) and 2) atoms interact in integer quantities. If you put those two together there is a common multiplier for a stochiometric equation that is related to the mass of a given atom in that stoichiometry. That multiplier is the the mole.

edit: I guess that's kind of a factor, but it's really more of an derived unit. If there was a new element discovered a mole would still describe it's stoichiometry, and IIRC that's how a lot of the periodic table was filled out my Mendelov.

[–] [email protected] 2 points 8 months ago (1 children)

No it's simply a big number. We are stuck with it due to history, but at its core it's a dimensionless quantity. You can do every single calculation without moles. Sure, yo may have to adjust some constants (boltzman constant vs gas constant for example), but it's not a unit in the same sense a meter or a second is.

[–] [email protected] 1 points 8 months ago

I don't know exactly what you'd call it, but respectfully, it's not just a big number.

Ignoring other isotopes (which, all you need to do to adjust for that is use the weighted average), if you have 12 grams of carbon, 63 of copper, etc you will have 6.02E23 molecules of each. The value is implied by the fact that again, atoms have a consistent mass and react in integer quantities. A mol could have been any value, but that's like saying that a meter could have been as well. The existence of some value that marries the atomic mass of each element to a quantity of atoms is inherit the same way pi is inherit to a circle.

[–] [email protected] 3 points 8 months ago

No u

[–] [email protected] 28 points 8 months ago (2 children)

Meanwhile, Brits will look you dead in the eye and say "I weigh 11 stone and 5 pounds"

[–] [email protected] 6 points 8 months ago (1 children)

A few years ago maybe!

[–] [email protected] 2 points 8 months ago (1 children)

Nah, they still do it. A British person gave their weight in stone to me recently. I asked if they could give it in kg, they could not. I asked how much a stone is in kg, they did not know.

[–] [email protected] 4 points 8 months ago* (last edited 8 months ago) (1 children)

Sorry, I meant my actual weight is 2 stone now than then!

[–] [email protected] 4 points 8 months ago

Oh, right. Mine is now 5 squared lakes.

[–] [email protected] 2 points 8 months ago

Bri#ish people be like "Oi love I got me here some jolly wogs how much is a stone gonna?"