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pressure in lungs

Hi! I've looked in all my textbooks and I'm really not sure how to answer this question :frown:

I've sat down and thought for a while and I just didnt know how to answer them! Anyway, here are the questions

Consider a sample of air within the lungs.
a) What is the approximate partial pressure of nitrogen gas and O2 gas in the lungs at 1 atmosphere total pressure?
I was thinking about using moles = mass/RMM but that just doesnt even look right!
b) On a deep sea diving expedition, a diver swims at a depth of 30metres. The tota pressure at this depth is 4 atmospheres. What us the partial pressure of nitrogen and oxygen gas in the lungs at this depth?
I havent even been told how to put together distance with partial pressure!!! :confused:

c) At the pressure mentioned in part (b), the gases become more soluble in the bloodstream. Explain the potential problems that the diver may have operating at this depth and on his return to the surface.
I'm guessing that the gases may change the molecular structure of the molecules in the blood. I dont know! :bawling:

And then it asks to sketch a graph to show how the partial pressure of a gas varies with the totak pressure of the system. Its hows a graph with total pressure/atm on the x axis (--->) lol and partial pressure of gas/atm on the y axis. I'm guessing again that the graph has an S shape. But that might be just me confusing concentration with pressure. :frown:

Please help :bawling:

Reply 1

Molsaka G

1

Not sure about the others, but for question c I think it is that nitrogen gets absorbed into the blood stream and collects at joints (this is because it will expand on return to the surface), causing decompression sickness.

Reply 2

BloodyValentine

14

The first 2 are chemistry questions but as i remember partial pressure = mole fraction x total pressure
And the third one is about the bends.

OP

the bends? :s:

Da Mouse

the bends? :s:

Hey where did my post go? :confused:

Yep the bends otherwise known as decompression sickness because the nitrogen in the blood stream expands when you return to the surface.

Reply 5

rupalini

2

Da Mouse

the bends? :s:

thats what divers get if they come up to the surface too quickly...check the other thread you posted this in for a better explanation :smile:

Reply 6

Molsaka G

1

rupalini

thats what divers get if they come up to the surface too quickly...check the other thread you posted this in for a better explanation :smile:

Oh I see there are 2 threads . . . :redface:

p(tot) = px + py + pz etc...

partial pressure = mole fraction X total moles

in air N2 is about 4/5 of the air by volume

volume is proportional to moles

so the partial pressure of N2 = 0.80 atmospheres
partial pressure of O2 = 0.2 atmospheres

just take it from there...

Reply 8

steve2005

17

Da Mouse

Hi! I've looked in all my textbooks and I'm really not sure how to answer this question :frown:

I've sat down and thought for a while and I just didnt know how to answer them! Anyway, here are the questions

Consider a sample of air within the lungs.
a) What is the approximate partial pressure of nitrogen gas and O2 gas in the lungs at 1 atmosphere total pressure?
I was thinking about using moles = mass/RMM but that just doesnt even look right!
b) On a deep sea diving expedition, a diver swims at a depth of 30metres. The tota pressure at this depth is 4 atmospheres. What us the partial pressure of nitrogen and oxygen gas in the lungs at this depth?
I havent even been told how to put together distance with partial pressure!!! :confused:

c) At the pressure mentioned in part (b), the gases become more soluble in the bloodstream. Explain the potential problems that the diver may have operating at this depth and on his return to the surface.
I'm guessing that the gases may change the molecular structure of the molecules in the blood. I dont know! :bawling:

And then it asks to sketch a graph to show how the partial pressure of a gas varies with the totak pressure of the system. Its hows a graph with total pressure/atm on the x axis (--->) lol and partial pressure of gas/atm on the y axis. I'm guessing again that the graph has an S shape. But that might be just me confusing concentration with pressure. :frown:

Please help :bawling:

You might find this helpful
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/henry.html

Graham's Law is about gas diffussion ...

OP

thanx for the help! :smile:

Reply 10

Da Mouse

OP

3