An inverted gas jar over water collects 50 cc of oxygen. The room temperature is 27^ C and the atmospheric pressure is 99.4 kPa . The water level inside the jar is equal to the level outside. Given that the saturation vapour pressure at 27^ C is 3.4 kPa , determine the number of moles of oxygen collected in the jar.

Step-by-step solution

Since the water level inside the gas jar is equal to the level outside, the total pressure inside the jar is equal to the atmospheric pressure. P_ ext total = 99.4 kPa The gas collected over water is a mixture of oxygen and water vapour. The partial pressure of oxygen is obtained by subtracting the aqueous tension (saturation vapour pressure of water) from the total pressure: P_ O ₂ = P_ total - P_ water P_ O ₂ = 99.4 kPa - 3.4 kPa = 96.0 kPa = 96 10^3 Pa Given: Volume, V = 50 cc = 50 10⁻⁶ m ^3 Temperature, T = 27^