Question

lung capacity was measured as 3.1 L at a body temperature of 37 ∘C and a pressure of 741 mmHg . How many moles of oxygen is in her lungs if air contains 21% oxygen?

Answer 1

First calculate total mole of gases in lung

Use ideal gas equation for calculation of mole of gas

Ideal gas equation

PV = nRT             where, P = atm pressure= 741 mmHg = 0.975 atm,

V = volume in Liter = 3.1 L

n = number of mole = ?

R = 0.08205L atm mol^-1 K^-1 =Proportionality constant = gas constant,

T = Temperature in K = 37⁰C = 273.15+ 37 = 310.15 K

We can write ideal gas equation

n = PV/RT

Substitute the value

n = (0.9753.1)/(0.08205310.15) = 0.11877 mole

total mole of gas in lung = 0.11877 mole

0.11877 mole = 100% then 21% = 0.11877 21/100 = 0.0249417 mole

0.0249417 moles of oxygen is in her lungs if air contains 21% oxygen.