Name: 液態電子 - 視頻週期表 (Liquid Electrons - Periodic Table of Videos)
Uploaded: 2021-01-14T10:15:15.000Z
Duration: 7 min 27 s
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[Dr. Robert Stockman] Look at that, that is very pretty!

We're gonna put some sodium into liquid ammonia.

虛擬句型

So what happens is that the sodium, ah, reacts,

it releases an electron, becomes sodium single plus,

and those electrons get solvated by the ammonia.

And it's a really unusual thing in chemistry,

to have just electrons themselves being solvated.

Here we have a Dewar, this is just like you would put...

a Thermos flask or something, you would put your

And in it we've got some solid CO2, cardice,

and acetone. So that brings the whole temperature

down to about -78C, and we need to do that

because ammonia boils at -33C. So we've got

We've just condensed some of that into this

sealed tube, which, currently, is not sealed,

but we're using this because it's got nice thick glass.

It'll obviously heat up because there's some solvation

going on, some heat of solvation, so we'll have to

just to stop all the ammonia from boiling off.

We have a big lump of sodium, cut some bits off that.

This is gonna go in there, and hopefully it will not

be too vigorous a reaction, there you go. So you can see

that blue colour already forming as the sodium reacts

I'll just dip that back in to keep it cold.

So it's releasing those electrons into the ammonia

solution. They're being solvated, which is why you get

So if we get the concentration of electrons high enough,

then it changes colour again, it goes to a sort of

metallic colour, so we need to add in a reasonable

And what will happen is that the ammonia with all the

electrons in, that's slightly more dense,

and so that separates out from just ammonia

And you can hear it fizzing as it reacts.

So we've got a really, really intense blue colour now.

Almost looks black. So let's put that in there.

I would have thought that would be enough,

See, we're already starting to see some of that bronze

gone from very deep blue to almost black.

We're starting to see some signs of this metallic sheen.

But we don't really want to put too much of that on,

of the electrons in the solution to a certain point where

We get the solvated electrons will look sort of metallic-y,

Well, we're reacting the sodium with the isopropanol,

So, all the electrons will be reacting away,

So we're getting this sort of gray sodium isopropoxide...

[Dr. Stockman] ...solution. Yeah, looks like an

it's making everything safe so that we can dispose of it.

The last remnants of this metallic solution here.

[Brady] Oh yeah, it looks metallic still!

[Brady] These electrons that are in there, like,

they're free, are they? They're just like roaming...

[Dr. Stockman] They're solvated, so the ammonia...

There are many amonias around the electrons...

and you can see it as this sort of metallic solution.

The electrons are getting less concentrated

and more concentrated up here where they're reacting.

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液態電子 - 視頻週期表 (Liquid Electrons - Periodic Table of Videos)

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