Answer to Question #311236 in General Chemistry for Zai

Question

Who dissolve faster oxygen + water at 1 atm or oxygen + water at 2 atm? Explain your answer.

Answer 1

Dissolved oxygen will increase as pressure increases. This is true of both atmospheric and hydrostatic pressures. Water at lower altitudes can hold more dissolved oxygen than water at higher altitudes. This relationship also explains the potential for "supersaturation" of waters below the thermocline - at greater hydrostatic pressures, water can hold more dissolved oxygen without it escaping. Gas saturation decreases by 10% per meter increase in depth due to hydrostatic pressure. This means that if the concentration of dissolved oxygen is at 100% air saturation at the surface, it would only be at 70% air saturation three meters below the surface.