Ideal Gas Example Problem - Constant Volume
Worked Chemistry Problems
The ideal gas law applies to real gases at low temperatures.
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Question The temperature of a sample of an ideal gas confined in a 2.0 L container was raised from 27 °C to 77 °C. If the initial pressure of the gas was 1200 mm Hg, what was the final pressure of the gas?

Solution

Step 1

Convert temperatures from Celsius to Kelvin

K = °C + 273

Initial temperature (T_{i} ): 27 °C

K = 27 + 273 K = 300 Kelvin T_{i} = 300 K

Final temperature (T_{f} ): 77 °C

K = 77 + 273 K = 350 Kelvin T_{f} = 350 K

Step 2

Using the ideal gas relationship for constant volume , solve for the final pressure (P_{f} )

P_{i} / T_{i} = P_{f} / T_{f}

solve for P_{f} :

P_{f} = (P_{i} x T_{f} ) / T_{i} P_{f} = (1200 mm Hg x 350 K) / 300 K P_{f} = 420000 / 300 P_{f} = 1400 mm Hg

Answer

The final pressure of the gas is 1400 mm Hg.