A2L Item 115
- Description: Identify the final temperature after an ideal gas undergoes a free expansion.
- Goal: Reasoning about temperature.
- Source: UMPERG-ctqpe186
- Keywords: Ideal Gas, Thermodynamics
The question for students:
Two moles of an ideal gas fill a volume of 10 liters with a pressure of 2.4 atm. The gas is thermally insulated from the surroundings. A membrane is broken which allows the gas to expand into the new volume which is 3 times as large as the old volume. The new temperature is …
- The same as before.
- Lower than before.
- Higher than before.
- Cannot be determined.
Commentary for teachers:
Answer
(1) Students may erroneously apply prior knowledge that gas cools as it expands. Some will likely think that the answer cannot be determined without more information.