Please help. calculate the partial pressure of oxygen gas Po2 at STP.

0.21 atm

Explanation:

From the question given above, the following data were obtained:

Partial pressure of N₂ (P₁) = 0.78 atm

Partial pressure of Ar (P₂) = 0.01 atm

Partial pressure of O₂ (P₃) =?

Since the system is at standard temperature and pressure (STP), the total pressure of the system is 1 atm.

Finally, we shall determine the partial pressure of O₂. This can be obtained as follow:

Partial pressure of N₂ (P₁) = 0.78 atm

Partial pressure of Ar (P₂) = 0.01 atm

Total pressure (Pₜ) = 1 atm

Partial pressure of O₂ (P₃) =?

Pₜ = P₁ + P₂ + P₃

1 = 0.78 + 0.01 + P₃

1 = 0.79 + P₃

Collect like terms

1 – 0.79 = P₃

P₃ = 0.21 atm

Therefore, the partial pressure of O₂ is 0.21 atm.