B2 中高級 美國腔 500 分類 收藏
Hello everyone. Today I will tell you about the most active and unusual metal on earth: Cesium.
Cesium is an active alkaline metal, which is located near the bottom of the periodic table of chemical elements
only Francium(Fr) can be more active than Cesium(Cs).
but that metal is radioactive and an un insignificant amount of it
was obtained in its pure form to do any experiments with it.
because of its high activity, metallic Cesium is being stored in special ampules
and inert atmosphere of either Argon or Hydrogen.
Appearance wise, Cesium has a yellowish tint like gold.
but the price for Cesium is still higher than Gold
due to its extremely small sales market and its highest activity,
price of Cesium can reach over €100 per gram.
The vial, you should see on the screen, is 50 grams of cesium.
Just imagine it's cost.
Cesium is unusual, that it has a very low melting point,only 29℃.
If you take a vial of Cesium in hand,
you can see how quickly the metal begins to melt.
Even while Cesium is still in the vial, we can already conduct experiment with it.
If you leave the liquid Cesium, in a vial for some time,
it partially hardens, forming very beautiful crystals of pure Cesium
Also, due to Cesium's solidification, its volume is being significantly reduced
as can be clearly seen with a funnel formed from solidified Cesium in the ampule.
Now, lets proceed to the most interesting part: conducting experiments with Cesium.
Firstly, to get the Cesium out of the vial, I decided to melt it in the vial
and then pour out the liquid Cesium in kerosene.
However, something went wrong during that part.
【cracking and screaming】
The liquid Cesium instantly ignited in air, burning everything around it.
That happened most likely due to the fact that the Cesium in the vial was liquid
after the hammer happened, the top of the vial broke off, pouring Cesium onto the table.
You can see what happens next, the table is now out of use.
But that's okay, we still have more tables.
For further experiments, we get to buy another vial of Cesium.
Now I decided to do things differently: break the end of ampule with solid Cesium and then heat in kerosene
This all turned out well, gradually the liquid Cesium began to flow from the vial into the kerosene.
After reach it immediately lost its golden shine and get covered with a layer of oxides and peroxides.
Due to the impurity of water and oxygen in kerosene, I have decided to destroy
the vial with the remains of liquid Cesium by throwing it onto a wet wall.
After solidifying, the Cesium can be easily cut, even with a spatula.
And it is not just the most active, but also the softest metal in the world.
It resembles margarine for its softness.
For the first time on YouTube, you can now observe Cesium is being cut.
First, I took a piece of Cesium, and put it on a piece of wood.
Cesium melts from the oxidation reaction of oxygen in the air
and then self ignites with a beautiful magenta flame due to Cesium ions.
Cesium also behaves similarly on the napkin.
Furthermore, by analogy with Rubidium, I decided to conduct the reaction of Cesium with sand.
Igniting Cesium on sand, similarly to rubidium, Cesium reacts with the silica
which the sand consists of very calmly and forms a beautiful sandy surface and also, an amorphous silicon.
Next, I decided to let hot Cesium react with manganese sulfate, the response wasn't very rough.
But it is better that it was with sand, when it's formed a metal manganese.
The coolest reaction by far was Cesium with sulfur.
Where we throw the piece of Cesium in molten sulfur.
【crack and explosion】
In that reaction the two elements forms Cesium sulfide.
Also we decided to fuse copper with cesium,
with that an unusual compound was formed, the intermetallic compound of copper and cesium
which eventually decayed due to cesium's oxidation by atmospheric oxygen.
If you throw a piece of Cesium into the glass filled with ethanol, Cesium will self ignite even in alcohol,
coloring the flame of alcohol to beautiful purple due to Cesium ions.
Lastly, we decided to throw about 20 grams of Cesium in container filled with the ice water.
As you can see, Cesium explodes on the first contact with water.
Although not so strongly as it's sometimes portrayed in other videos.
Cesium has a variety of applications, these days metallic Cesium is used in the most accurate atomic clocks.
The error of which is only a second per 100 million years.
Also, Cesium is used in the new engines for orbital satellites.
Until about the early 2000s, before the rise of micro electronics,
Cesium has been widely used in photocells and motion sensors.
However, after the market has been flooded with cheap transistor analogies,
the need of such a number of manufacturing metallic cesium disappeared and the price had since arisen sharply.
And lastly, I would like to thank the company MEL Science.
Without them, the production of this video would have been impossible.
The Cesium was worth a lot of money, not mention the burning of the table.
It was all done for science, and so that you, my channel viewer,
who would learn a lot of about this amazing metal, Cesium.
Like the video if you enjoyed it, subscribe my channel, and also visit the website site of our sponsor, MEL Science.
Thank you for watching!


銫(Cs) - 地球上最活躍的金屬! (Cesium - The most ACTIVE metal on EARTH!)

500 分類 收藏
deghyp 發佈於 2019 年 12 月 28 日
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