Atmospheric Pressure & Boiling Point of Water: 20 C

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Discussion Overview

The discussion revolves around the relationship between atmospheric pressure and the boiling point of water, specifically addressing the conditions required for water to boil at 20°C. The scope includes theoretical applications of the Clausius-Clapeyron equation and considerations of purity in water.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the atmospheric pressure needed for water to boil at 20°C.
  • Another participant suggests using the Clausius-Clapeyron equation to find the answer.
  • A different participant expresses a need for a general explanation of the equation, indicating a lack of familiarity with the topic.
  • One participant mentions that the calculation assumes pure water and notes that impurities like salt can affect the boiling point.
  • A participant initially calculates an atmospheric pressure of 18,900 mbar but later questions the accuracy of this value, suggesting a possible arithmetic error.
  • Another participant references a Wikipedia source that states the atmospheric pressure for boiling water at 20°C is around 25 mbar.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct atmospheric pressure for boiling water at 20°C, with differing calculations and references to external sources. Uncertainty remains regarding the initial calculation provided.

Contextual Notes

Some assumptions about the purity of water and the specific conditions under which the Clausius-Clapeyron equation applies are mentioned but not fully explored. The discussion includes potential arithmetic errors in calculations.

ybhathena
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What does the atmospheric pressure have to be to make the boiling point of water 20 C?
 
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Google "Clausius-Clapeyron equation" and apply it...
 


Oh ok that seems to be what I need. Its a little bit advanced, could you explain the general idea of how to use this formula? I am a bit new
 


Hmm... Well that would be a very involved answer. You should be able to handle it if you know basic algebra. I'm assuming you were given the values to plug in. Also it assumes that it's pure water. Impurities such as salt require the chemical process to first break the hydrogen bonds making water boil at a higher temperature.

I did it for you quickly and got an an answer of 18,900m rounded.

Edit: Actually that can't be correct. That's the limit where water boils at the internal temperature of a human, 37 C. I must have messed up my arithmetic.
 
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