Question

Can a barometer be used to measure just the partial pressure of oxygen in the atmosphere?

Answer 1

Ans. NO
# Partial pressure of oxygen = Pressure exerted by O₂ in the atmospheric O₂

# A barometer measures the total air pressure in the atmospheric. The total air pressure or atmospheric pressure is the sum of partial pressures of N₂, O₂ and all other gases in the atmosphere.

Since the barometer can’t differentially measure the pressure exerted by O₂ alone, it can’t measure the partial pressure of oxygen.

# However, knowing the atmospheric pressure using a barometer and mole fraction of O₂ by some other method, the partial pressure of O₂ can be calculated (but NOT measured) as follow-

Partial pressure of O₂ = Mole fraction of O₂ in air x Atmospheric pressure