A resting person requires 14.5 L of oxygen per hour to maintain metabolic activities. Such a person breathes in 0.480 L of air at approximately 25.0 degrees celsius with each breath. The inhaled air is 20.9% while the exhaled air is 16.3%. How many oxygen molecules does a resting person inhale per breath?

The consumption per hour is not needed to answer this. The way it is worded, the O2 content of the exhaled breath is also not needed. Just compute the number of O2 molecules in 0.480 liters of air at NTP (25 C and 1 atm). I get about 0.00410 moles of O2. Convert that to molecules in the usual way.

Only about 78% of that (163/209) gets absorbed into the bloodstream

To find the number of oxygen molecules that a resting person inhales per breath, we need to use the information provided about the volume of air inhaled and the percentage of oxygen in the two air samples.

First, let's convert the temperature from Celsius to Kelvin. The equation to convert Celsius to Kelvin is: K = °C + 273.15

So, 25.0 degrees Celsius is equal to 25.0 + 273.15 = 298.15 Kelvin.

Next, let's calculate the amount of oxygen inhaled per breath. We can do this by multiplying the volume of air inhaled (0.480 L) by the percentage of oxygen in the inhaled air (20.9%).

Oxygen inhaled = Volume of air inhaled × Percentage of oxygen in inhaled air
= 0.480 L × 0.209
≈ 0.10032 L

Now, let's convert the volume of oxygen inhaled per breath to moles. To do this, we need to use the ideal gas law, which states: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is temperature in Kelvin.

Rearranging the ideal gas law equation, we get: n = (PV) / (RT)

Let's assume the pressure is standard atmospheric pressure, which is approximately 1 atm.

Moles of oxygen inhaled = (Pressure × Volume of oxygen inhaled) / (Ideal gas constant × Temperature)
= (1 atm × 0.10032 L) / (0.0821 L·atm/mol·K × 298.15 K)
≈ 0.0042 moles

Finally, let's convert moles to the number of oxygen molecules. We know that one mole of any substance contains Avogadro's number of particles, which is approximately 6.022 x 10^23.

Number of oxygen molecules inhaled = Moles of oxygen inhaled × Avogadro's number
= 0.0042 moles × 6.022 x 10^23 molecules/mole
≈ 2.5244 x 10^21 oxygen molecules

Therefore, a resting person inhales approximately 2.5244 x 10^21 oxygen molecules per breath.