Question

A young male adult takes in about 5.16 x 104 m³ of fresh air during a normal breath. Fresh air contains approximately 21% oxygen. Assuming that the pressure in the lungs is 0.967 x 105 Pa and air is an ideal gas at a temperature of 310 K, find the number of oxygen molecules in a normal breath.

Answer 1

Step-by-step explanation:

To find the number of oxygen molecules in a normal breath, we can use the ideal gas law equation, which relates the pressure, volume, temperature, and number of molecules of a gas:

PV = nRT

Where:

P = Pressure (in Pa)

V = Volume (in m³)

n = Number of moles

R = Ideal gas constant (8.314 J/(mol·K))

T = Temperature (in K)

First, let's calculate the number of moles of air inhaled during a normal breath:

V = 5.16 x 10^4 m³ (Volume of air inhaled)

P = 0.967 x 10^5 Pa (Pressure in the lungs)

R = 8.314 J/(mol·K) (Ideal gas constant)

T = 310 K (Temperature)

Rearranging the equation, we get:

n = PV / RT

n = (0.967 x 10^5 Pa) * (5.16 x 10^4 m³) / (8.314 J/(mol·K) * 310 K)

n ≈ 16.84 mol

Next, let's find the number of oxygen molecules inhaled. Since fresh air contains approximately 21% oxygen, we can multiply the number of moles by the fraction of oxygen in the air:

Number of oxygen molecules = n * (0.21)

Number of oxygen molecules ≈ 16.84 mol * 0.21

Number of oxygen molecules ≈ 3.54 mol

Finally, we'll convert the number of moles of oxygen molecules to the actual number of molecules by using Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol:

Number of oxygen molecules = 3.54 mol * (6.022 x 10^23 molecules/mol)

Number of oxygen molecules ≈ 2.13 x 10^24 molecules

Therefore, in a normal breath, there are approximately 2.13 x 10^24 oxygen molecules.