Continuing my experimentation with bismuth

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Discussion Overview

The discussion revolves around the properties and experimental observations of bismuth, particularly its behavior when exposed to heat and air, as well as its physical characteristics such as density and diamagnetism. Participants share personal experimentation experiences and inquire about the underlying chemical and physical principles involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Experimental/applied

Main Points Raised

  • One participant notes that bismuth exhibits colorful oxides only when hot and exposed to air, while remaining shiny and silvery when polished with a scouring cream.
  • Another participant suggests that heat acts as a catalyst in the oxidation process, although this claim is later contested.
  • A participant highlights that heat and catalysts speed up reactions for different reasons, prompting a clarification and acknowledgment of the distinction.
  • One participant observes that solid bismuth floats on molten bismuth, similar to water, and confirms this observation from their own melting experiment.
  • Another participant mentions bismuth's diamagnetic properties, noting that it is repelled by a magnetic field and suggesting an experiment with neodymium magnets.
  • A later reply acknowledges the weak diamagnetism of bismuth but emphasizes that it is stronger than any other material the participant has encountered.

Areas of Agreement / Disagreement

Participants express differing views on the role of heat and catalysts in chemical reactions, indicating a lack of consensus on this point. Other observations about bismuth's properties appear to be generally accepted among participants.

Contextual Notes

Some discussions involve assumptions about chemical kinetics and the definitions of catalysts versus heat, which remain unresolved. The implications of bismuth's properties in practical applications are also touched upon but not fully explored.

Who May Find This Useful

This discussion may be of interest to those experimenting with materials science, particularly in the context of metal properties, chemical reactions, and physical experiments involving bismuth.

BetaZeta2016
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The more i study this strange element, the more interesting it becomes.

I found that bismuth only shows it's colorful oxides when exposed to air while hot/molten.

I decided to go outside and polish the sample using an abrasive liquid known in Brazil as "Saponáceo Cremoso".
Don't know what it's called in english-speaking countries.

Edit: It's called "Scouring cream" in english.

Anyway, it's used to polish aluminum cookware as well as any other metal surfaces.

So i took my bismuth sample out and started polishing.

The metal finally showed it's natural appearance: A lustrous, shiny and silvery material that resembles lead or iron.

But something more happened: It didn't oxidize. Even after being exposed to air, water or even the oils from my hand, it's still shiny, without any noticeable color change.

But when molten, it tarnishes instantaneously!

Anyone knows why?
 
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BetaZeta2016 said:
So the heat acts as a catalyst here.

No. Catalyst is a catalyst, heat is a heat. Both speed up the reaction, but for completely different reasons.
 
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Borek said:
No. Catalyst is a catalyst, heat is a heat. Both speed up the reaction, but for completely different reasons.

Oh, nice. Thank you for clarifying :smile:.
 
As you were melting Bismuth and already messing up one pan: Did you observe the solid bismuth to float on the melt? Bismuth is one of the few substances (like water) where the solid is less dense than the melt.
 
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DrDu said:
As you were melting Bismuth and already messing up one pan: Did you observe the solid bismuth to float on the melt? Bismuth is one of the few substances (like water) where the solid is less dense than the melt.

Yes, i did!
While the bismuth was molten, there was a small chunk floating on the top of the liquid.

I won't do it on the kitchen again. One pan just went to the trash because of this hehe. :biggrin:
 
Bismuth is also a relatively strongly diamagnetic substance, i.e. it gets repelled by a magnetic field. If you mount your probe on a string and bring a strong magnet close (best one of these small neodymium magnets) it will turn away.
 
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Cool experiment too! I tried it with some magnets from old hard drives.

Bismuth diamagnetism is very weak.
But still stronger than any other material i have ever seen.
 

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