Heating boosts molecular collisions

Steps:

• Heating transfers energy to gas molecules.
• This raises their average kinetic energy and speed.
• Faster molecules travel shorter distances between wall collisions.
• Resulting in more frequent hits on the container walls.

Why D is correct:

• Kinetic molecular theory states pressure arises from molecular collisions with walls; increased temperature raises collision frequency via higher speeds (from PV = nRT, where T rise at fixed V boosts P).

Why the others are wrong:

• A: Kinetic energy increases with heat, per the ideal gas law.
• B: Individual molecules are point masses and do not expand.
• C: Molecular mass remains constant regardless of temperature.

Final answer: D