Calculate Temperature for White to Grey Tin Conversion | Thermodynamic Data

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Discussion Overview

The discussion revolves around calculating the temperature at which white tin converts to grey tin, focusing on thermodynamic data and the implications of phase stability and kinetics. The conversation touches on theoretical and practical aspects of this phase transition.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant expresses uncertainty about the calculation and seeks guidance on the appropriate equation to use.
  • Another suggests that the question might be better suited for the materials engineering forum, indicating a lack of confidence in addressing the problem.
  • A participant notes that the phase transition may be metastable at certain temperatures, suggesting that while thermodynamically white tin should convert to grey tin, the kinetics may not allow for this conversion to occur readily.
  • There is a query about the specific reaction related to the conversion of white tin to grey tin.
  • One participant explains that grey tin is more stable than white tin at lower temperatures and provides an anecdote about historical instances of tin pest, illustrating the slow conversion process at room temperature.
  • Another participant proposes using Gibbs free energy to determine the temperature at which the reaction becomes spontaneous, mentioning that free energy equals zero indicates no overall reaction.
  • A later reply reiterates the Gibbs free energy approach and discusses the interpretation of the conversion process occurring over time, suggesting that thermodynamic data alone may suffice for the calculation.

Areas of Agreement / Disagreement

Participants express various viewpoints on the calculation method and the nature of the phase transition, with no consensus reached on a definitive approach or solution. The discussion remains unresolved regarding the specifics of the calculation and the implications of metastability.

Contextual Notes

Participants mention the potential need for additional considerations beyond thermodynamic data, such as the kinetics of the phase transition and the metastable nature of white tin. There are references to historical cases and literature that may provide further context but are not fully explored in the discussion.

physicsss
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Based on thermodynamic data found in your textbook, calculate the temperature at which white tin will convert into grey tin.

I have no idea how to do this...what equation should I use?
 
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Ah, the "tin pest"... I don't know for sure how to do it, but I think you might have better luck in getting help if you ask the question in the materials engineering forum.
 
To me it sounds like one would need more than thermodynamic data. The phase might be metastable at certain temperatures, i.e. thermodynamically white tin should convert to grey tin, but the kinetics are not sufficient for the conversion.
Wow, I really wouldn't know how to tackle this one. Do notify us when you know more ;)
 
what's the reaction pertaining to this problem?
 
Gray Sn is an allotrope of Sn which is more stable than white Sn at lower temperatures. Actually, at room temp, white Sn is slowly turning into gray, though the process is extremely slow. There's a case I read about involving a old pipe-organ in Germany, which had pipes made of Sn that crumbled (became gray Sn) during a very cold winter day. Also, pewter, which is an alloy of Sn, should be protected from low temperatures. "Mellor's Modern Inorganic Chemistry" has info on this so-called "tin pest."
 
Interesting. Well, one general way to solve this problem is to use Gibb's free energy, find the temperature at which the reaction is spontaneous, when free energy equals 0. Zero indicates no overall reaction, while anything below indicates an overall reaction. You can either find the net free energy by subtracting the free energy of the reactant from the product.

Although there may be a more mathematically elegant way to do this.
 
GCT said:
Well, one general way to solve this problem is to use Gibb's free energy, find the temperature at which the reaction is spontaneous, when free energy equals 0.

OK, if the formulation "will convert to grey tin" should be interpreted as over time, maybe not even within some millennia, but it will happen, then the procedure sounds right and you need only thermodynamical data.
 

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