How much gas is released given partial pressure

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Discussion Overview

The discussion revolves around calculating the amount of nitrogen gas released from blood when a deep sea diver ascends from a depth where the partial pressure of nitrogen is significantly higher than at the surface. The problem involves concepts of gas solubility, partial pressures, and volume calculations, specifically in the context of a homework problem.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant states that the amount of nitrogen gas released is 0.389 liters, while another claims it is 0.35 liters, indicating a discrepancy in their calculations.
  • A different participant reports a value of 0.385 liters, suggesting further variation in the answers provided.
  • Another participant calculates the amount of dissolved nitrogen at the surface to be 2.78 x 10-3 mol and argues that under higher pressure, the amount of dissolved gas increases proportionally, resulting in 0.0139 mol at 4 atm.
  • This participant further explains that 0.0139 moles of nitrogen gas would occupy 0.356 liters at 1 atm and 37°C, but emphasizes that this does not account for the nitrogen that remains dissolved in the blood at the surface, leading to a conclusion that the correct answer is below 0.3 liters.

Areas of Agreement / Disagreement

Participants express differing calculations and interpretations of the problem, with no consensus on the correct amount of nitrogen gas released. Multiple competing views remain regarding the final answer.

Contextual Notes

Participants have not fully resolved the assumptions regarding the solubility of nitrogen at different pressures and the amount that remains dissolved after ascent, which affects their calculations.

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Homework Statement


The solubility of N2 in blood at 37 degree and at a partial pressure of 0.8 atm is 5.6 x 10-4 mol/L?
a deep sea diver breathes compressed air with the partial pressure of N2 equal to 4 atm. Assume that the total volume of blood in the body is 5 L. Calculate the amount of N2 gas released (in liters at 37 degree and 1 atm) when the diver returns to the surface of water, where the partial pressure of N2 is 0.8 atm2. The attempt at a solution

I got the answer of 0.389, but someone told me it is 0.35. Is my answer correct?
 
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I got even different value. Please show how you got your result.
 
Thanks, the answer is 0.385
 
No!

At the surface amount of dissolved nitrogen is 5 L * 5.6x10-4 mol/L = 2.78x10-3 mol.

Under water pressure of the nitrogen is five times larger, so the amount of dissolved gas is also five times larger - that means 5 * 2.78x10-3 mol = 0.0139 mol.

0.0139 moles of gas at given conditions (1 atm, 37°C) occupies 0.356 L - but it is not the correct answer! That would be the correct answer if all gas were released, but nitrogen dissolves in blood even on the surface. We have already calculated how much will be left dissolved, we have to take it into account.

Correct answer is below 0.3L.
 

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