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422 Chapter 8 | Gases
Solution
The gases behave independently, so the partial pressure of each gas can be determined from the ideal gas equation, using :
The total pressure is given by the sum of the partial pressures:
Check Your Learning
A 5.73-L flask at 25 °C contains 0.0388 mol of N2, 0.147 mol of CO, and 0.0803 mol of H2. What is the total pressure in the flask in atmospheres?
Answer: 1.137 atm
Here is another example of this concept, but dealing with mole fraction calculations.
Example 8.15
The Pressure of a Mixture of Gases
A gas mixture used for anesthesia contains 2.83 mol oxygen, O2, and 8.41 mol nitrous oxide, N2O. The total pressure of the mixture is 192 kPa.
(a) What are the mole fractions of O2 and N2O? (b) What are the partial pressures of O2 and N2O? Solution
The mole fraction is given by and the partial pressure is PA = XA PTotal.
For O2,
and For N2O,
and
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