Hello, I was wondering if anyone could help me with this? I\'m not sure how to d

Question

Hello, I was wondering if anyone could help me with this? I'm not sure how to do it. Thank you! My PV value is 214.2

Also, I have an additional question not shown on the paper :

How much air do you respire... per hour? per day? per week? per year?

You know how much air reaches your lungs' alveoli each minute(PV), but how much Oxygen do you actually absorb into your body? Here is the percent amount of different gases in the air that enters your lungs and in the same air as it leaves your lungs. From Table the air that you inhale is 20.9% Oxygen. When you exhale that same air, only 15.8% of it is Oxygen. On the other hand, 0.04% of the air you inhale is Carbon dioxide, and when you exhale that same air, 4.0% of it is CO2. The human body does not use Nitrogen from the atmosphere, so the percent of the air you inhale/exhale that is N2 remains unchanged at 79.0% (your body does not absorb or produce N2).Using the information in Table 4 and your value for PV, what volume of O2 do you consume:

Explanation / Answer

(1) How much Oxygen does an average person need in a day to live?
3 sources:
    (a) According to NASA the average person needs 0.84 kg of O2 per day (day and night activity).

    (b) According to MadSci: The amount of air breathed by an average adult varies from 6 Litre/minute (when at rest) to 50 Litre/minute after hard exercise. So, at rest the amount of Oxygen absorbed by the blood in the lungs is 300 milliLitre/minute to 3,500 mL/minute.
            My Calculations for a person at rest: In 1 day the volume of O2 absorbed by a person at rest is 300mL/minute x 60 minute/hour x 24 h/day = 432,000 mL/day or 432 L/day. Since the mass of 1 mole of O2 is 32 gram and 1 mole of any gas has a volume of 22.4 L, the number of mole/day is 432 L/day / 22.4 L/mole = 19.28 mole.  
The mass of O2 needed per day is then 19.28 mole x 32 gram/mole = 617 gram or 0.617 kg of Oxygen per day, which is less than the NASA figure.

            My Calculations for a person doing hard exercise all day:  In 1 day the volume of O2 absorbed by a person at rest is 3,500 mL/minute x 60 minute/hour x 24 h/day =5,040,000 mL/day or 5,040 L/day. Since the mass of 1 mole of O2 is 32 gram and 1 mole of any gas has a volume of 22.4 L, the number of mole/day is 5,040 L/day / 22.4 L/mole = 225 mole.  
The mass of O2 needed per day is then 225 mole x 32 gram/mole = 7,200 gram or 7.2 kg of Oxygen per day, which is much more than the NASA figure. This is an unrealistic figure because a person doesn't do hard exercise day and night, but it does give an upper limit to Oxygen consumption for the average person.

An aside: About 5L of blood passes through your lungs every minute. Adult does from 12 to 18 breaths/minute.
, 'one does not breathe the entire lungs volume with every average breath, but only a small bit, I think around 500 ml -- called the tidal volume. A yawn or a sigh will force one to breath more as will deep sleep'. Lungs can hold up to 4 to 6 L -- called the Vital Capacity.
'Inspiratory reserve: the room for extra air beyond a normal tidal breath is about 3 L.
Expiratory reserve: the amount that can be forcefully expired beyond a normal tidal breath (exhalation) is 1.1 L.
Residual Volume: that which is left in the lungs after the most forceful exhalation is 1.2 L.'

Very roughly 5% of Volume of air is consumed in each breath (about 21% O2 in and about 16% O2 out).
CO2 output is another issue not covered here.

        (c) Body tissues need 14.7 L of Oxygen/hour. So, in 1 day they need 14.7 L/h x 24h/day = 352.8 L/day.
This is 352.8 L/day/22.4L/mole = 15.75 mole/day.
Which is 15.75 mole/day x 32 gram/mole = 504 gram/day or 0.504 kg/day of Oxygen. This is the absolute minimum required. This confirms we are in the right ball park.

We will use the 3 following figures:
0.617 kg for an average person at rest
0.84 kg for an average person going about his regular duties, including sleeping
7.2 kg for an average person that does continuous heavy exercise day and night (just to make a comparison).

The average adult at rest inhales and exhales something like 7 or 8 liters (about one-fourth of a cubic foot) of air per minute. That totals something like 11,000 liters of air (388 cubic feet) in a day.

The air that is inhaled is about 20-percent oxygen, and the air that is exhaled is about 15-percent oxygen, so about 5-percent of the volume of air is consumed in each breath and converted to carbon dioxide. Therefore, a human being uses about 550 liters of pure oxygen (19 cubic feet) per day

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