Answer: Perfectly elastic.
- A Perfectly inelastic
- B Perfectly elastic
- C Partially elastic
- D Random and energy losing
Correct answer: B. Perfectly elastic
Explanation: The kinetic theory assumes collisions between gas particles, and with container walls, are perfectly elastic, so kinetic energy is conserved.

Boyle's law: at constant temperature the pressure of a fixed mass of gas is inversely proportional to its volume (P ∝ 1/V), so the P–V plot is a hyperbola — halving the volume doubles the pressure. Image: Reginaprice2013, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Discover why gases expand to fill any container while liquids flow and solids hold their shape. Master the gas laws, the ideal gas equation, and the reasons real gases deviate from ideal behavior.