V = maximum capacity of human lung = 3 liter = 3 x 0.001 m³ = 0.003 m³ (Since 1 liter = 0.001 m³)
P = pressure of oxygen = 21.1 kilo pascal = 21.1 x 1000 = 21100 Pa (since 1 kilo = 1000)
T = temperature of air = 295 K
n = number of moles of oxygen
Using the ideal gas equation
PV = n RT
inserting the above values in the equation
(21100) (0.003) = n (8.314) (295)
n = 0.026 moles
