For half an hour, a person in a calm state takes 400 breaths, with each of which 700 cm3 of air passes

For half an hour, a person in a calm state takes 400 breaths, with each of which 700 cm3 of air passes through the lungs. What mass of air passes through the lungs of a person during this time?

Let’s calculate the total air volume:
400 * 700 = 28000 cm ^ 3 = 0.28 m ^ 3.
The mass of a substance is determined by the formula m = ρ * v where ρ is the density of the substance, v is its volume. The air density at normal pressure is 1.269 kg / m ^ 3, then the air mass will be equal to:
1.269 * 0.28 = 0.36 kg.