A2L Item 114

Goal: Problem solving with the ideal gas law

Source: UMPERG-ctqpe184

Two moles of an ideal gas fill volume V = 10 liters at pressure P = 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 pressure is:

  1. .4 atm
  2. .8 atm
  3. 1.2 atm
  4. 1.6 atm
  5. 2.4 atm
  6. None of the above
  7. Cannot be determined

Commentary:

Answer

(2) Some students may wonder about the applicability of the ideal gas
law for free expansion. Some may respond (7) thinking that since gas
cools as it expands, they do not know what the final temperature is and
cannot, therefore, use the ideal gas law.