hard · MCAT chem-phys
A rigid, perfectly insulated container is divided by a removable partition. One side holds 1 mol of an ideal gas at temperature T_0; the other side is fully evacuated. The partition is suddenly removed, and the gas expands irreversibly to fill the entire container. No stirring device or external motor is present, and the container exchanges no heat or matter with the surroundings.
How does the final gas temperature compare to T_0, and what is the correct justification?
- The temperature stays the same, since no heat enters and no work is done on anything, so internal energy cannot change
- The temperature falls, because the gas does work expanding into the larger available volume even though no piston is present
- The temperature rises, because the entropy increase of an irreversible process must be paid for by a rise in internal energy
- The temperature falls, because molecules collide less often at lower density, lowering their average kinetic energy
Sign up free to see the explanation and track your rank →
More MCAT chem-phys practice
- Which term describes the final state where no net heat flow occurs?
- What term describes the molecule with internal symmetry despite having chiral centers?
- An infrared (IR) spectrum of an unknown organic compound sho… — Which functional group is
- What is the molecular mechanism by which the catalyst achieves this increase?
- Which mechanism is occurring?
- According to the Critical Analysis and Reasoning Skills (CARS) methodology, which test sho
- Which reactant is the limiting reagent?
- How many moles of NH_3 are theoretically produced?