The solubility of oxygen in lakes high in the Rocky Mountains is affected by the altitude. If the solubility of O₂ from the air is 2.67 * 10^-4 M at sea level and 25^$\circ$C, what is the solubility of O₂ at an elevation of 12,000 ft where the atmospheric pressure is 0.657 atm Assume the temperature is 25^$\circ$C, and that the mole fraction of O₂ in air is 0.209 at both 12,000 ft and at sea level. A) 3.66 * 10^-5 M B) 1.75 * 10^-4 M C) 2.67 * 10^-4 M D) 4.06 * 10^-4 M E) None of the above.

Question

Quizplus · Accepted Answer

The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas in contact with the liquid. At 12,000 ft elevation, the atmospheric pressure is 0.657 atm, so the partial pressure of oxygen in air (0.209 mole fraction) is 0.657 x 0.209 = 0.137 atm. Using the solubility constant for oxygen at 25°C, we can calculate the solubility of oxygen at this partial pressure:

solubility = (0.137 atm / 1 atm) x (2.67 x 10^-4 M) = 7.35 x 10^-5 M = 1.75 x 10^-4 M = 1.75 x 10^-4 M

Therefore, the best choice is B.

The Solubility of Oxygen in Lakes High in the Rocky ∘\circ∘

The Solubility of Oxygen in Lakes High in the Rocky $\circ$