Temperature physical or chemical change

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Discussion Overview

The discussion revolves around the relationship between temperature changes and their potential to induce physical or chemical changes in substances. Participants explore whether temperature alone, without other reactions, can lead to chemical changes, particularly using water and nitrogen dioxide as examples.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant asserts that increasing or decreasing temperature and changing states of matter constitutes a physical change, questioning if temperature can cause a chemical change without combustion.
  • Another participant challenges the initial claim, suggesting that temperature changes can indeed lead to chemical changes, citing water as an example.
  • A third participant confirms their agreement with the idea that temperature can induce chemical changes.
  • Further, a participant explains that at very high temperatures, compounds like water will dissociate into hydrogen and oxygen, and mentions nitrogen dioxide as another example where temperature affects molecular composition.
  • The decomposition of nitrogen dioxide at elevated temperatures is discussed, highlighting that it can break down into nitrogen monoxide and oxygen, with the reverse occurring upon cooling.

Areas of Agreement / Disagreement

Participants express differing views on whether temperature changes alone can cause chemical changes, with some supporting the idea while others remain skeptical. The discussion does not reach a consensus.

Contextual Notes

Participants reference specific temperature thresholds and conditions under which chemical changes may occur, but the discussion does not clarify the precise definitions of physical versus chemical changes or the assumptions underlying these claims.

AMan24
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If you Increase or decrease temperature and change states of matter, that's a physical change.

But are there any circumstances where temperature can cause a chemical change? Like if increasing temperature could break the bonds between the atoms and separate them? And I don't mean a combustion reaction. I'm talking about just temperature change.

And if temperature can cause chemical change, then what if you heat H2O to really high temperatures? Like super high temperatures, would it break up into H2 and O2?
 
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AMan24 said:
temperature is a chemical change

That's purely nonsensical as stated. I guess what you mean is "are there any circumstances where change in temperature produces a chemical change".

Yes. Water example is a good one.
 
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yeah that's exactly what i meant
 
Every compound will dissociate at very high temperatures , the water you mention will become a mix , continually breaking apart and recombining ...

At more manageable temperatures there is nitrogen dioxide ... at low temperatures it exists as N2O4 molecules warm it up and there will be more and more NO2 molecules

At 150C it will decompose 2 NO2 → 2 NO + O2 ...cool it down and it recombines.
 

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