Answer:
To calculate the number of moles of oxygen in the lung, we can use the ideal gas law:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
We are given that the volume of the lung is 3.0 liters, or 0.003 m^3. We can assume that the pressure is equal to atmospheric pressure, which is approximately 101.3 kPa. The temperature can be converted from Celsius to Kelvin by adding 273.15, so T = 20.0 + 273.15 = 293.15 K.
We can rearrange the ideal gas law to solve for n:
n = PV/RT
Substituting the values we have, we get:
n = (101.3 kPa)(0.003 m^3)/(8.314 J/(mol K))(293.15 K)
n = 0.000372 mol
Therefore, there are approximately 0.000372 moles of oxygen in the lung.