Question

In: Physics

A. A person’s lungs can hold 6.0 L (1 L = 10-3 m3) of air at...

A. A person’s lungs can hold 6.0 L (1 L = 10-3 m3) of air at body temperature (310 K) and atmospheric pressure (101 kPa). Given that air is 21% oxygen, find the number of oxygen molecules in the lungs. [Ans: 3.0 x 10^22]

B. (Continued from the previous question) If the person now climbs to the top of a mountain, where the air pressure is half that at the base, does the number of molecules in the lungs change? If so, what is the number of oxygen molecules in the lungs? [Ans: 3.1 x 10^21]

Expert Solution

We have the ideal gas equation,

Where P is pressure, V is volume, T is temperature, n is no of moles of gas present in the system, and R = 8.31 J/mol.K is universal gas constant.

Therefore total number of moles of gas that a person's lungs can hold is

We know that,

One mole of any substance = 6.022 X 1023 particles

Therefore, total number of gas particles in a person's lungs are

Given that the gas contains 21 % Oxygen. So, the number of Oxygen particles in a person's lungs are

(B)

If the pressure become half of the original pressure then from the equation

the total number of particles will also get half of the original.

So, the number of oxygen molecules in the lungs at this height is

NOTE: The answer printed in your text is mistaken. However there are so many facts that can change the number of particles, like, if u climb a mountain the temperature will also change and this will effect the number of particles of Oxygen present in the lungs.

genius_generous answered 2 years ago

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