Question

Observe yourself breathing and count the number of times you inhale per second. During each breath you probably inhale 0.66 L of air. Assume the pressure is 1 atm and the temperature is 20∘C. Only about 21% of air is O2. 1. How many oxygen molecules do you inhale if you are at sea level?

Answer 1

To solve this exercise it is necessary to apply the concepts related to Robert Boyle's law where:

`PV=nRT`

Where,

P = Pressure

V = Volume

T = Temperature

n = amount of substance

R = Ideal gas constant

We start by calculating the volume of inhaled O_2 for it:

`V = 21\% * 0.66L`

`V = 0.1386L`

Our values are given as

P = 1atm

T=293K
`R = 0.083145kJ*mol^(-1)K^(-1)`

Using the equation to find n, we have:

`PV=nRT`

`n = (PV)/(RT)`

`n = ((1)(0.1386))/((0.0821)(293))`

`n = 5.761*10^(-3)mol`

Number of molecules would be found through Avogadro number, then

`\#Molecules = 5.761*10^(-3)*6.022*10^(23)`

`\#Molecules = 3.469*10^(21) molecules`