A student makes four statements about what happens when molecules from a 400 K gas collide with molecules from a 300 K gas that has just been brought into contact with it.
I. On average, molecules from the hotter gas lose kinetic energy during the collisions.
II. On average, molecules from the colder gas gain kinetic energy during the collisions.
III. Individual collisions can sometimes transfer energy from a cold molecule to a hot one.
IV. After a single collision the two gases must already be in thermal equilibrium.
Which statement is incorrect?
a) Only III is incorrect.
b) Both II and IV are incorrect.
c) Only IV is incorrect.
d) Only I is incorrect.