Dalton's law of partial pressures
A gas mixture at a total pressure of 1.0 atm contains 0.5 mol N2, 0.3 mol O2, and 0.2 mol CO2. What is the partial pressure of O2?
Answer B: explanation for every choice
A
This is the partial pressure of CO2.
B
Correct. Mole fraction of O2 = 0.3/1.0 = 0.3, so PO₂ = 0.3 × 1.0 atm = 0.3 atm.
C
This is the partial pressure of N2.
D
This is the total pressure of the mixture.
TakeawayPartial pressure = mole fraction × total pressure.
Equation usedDalton's law of partial pressures
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