Question

An iron sample heated to 90°C is immersed in water at 22°C. Which statement describes what happens to the molecular motion of the substances?

A) The molecular motion of both the iron and water increases.
B) The molecular motion of the iron increases, while the molecular motion of the water decreases.
C) The molecular motion of the iron decreases, while the molecular motion of the water increases.
D) The molecular motion of both the iron and water decreases.

Answer 1

The molecular motion of the iron decreases, and the molecular motion of the water increases due to heat transfer.

Step-by-step explanation:

When an iron sample heated to 90°C is immersed in water at 22°C, the molecular motion of the iron decreases while the molecular motion of the water increases. This occurs due to heat transfer from the iron to the water until thermal equilibrium is reached. The iron loses thermal energy which makes its molecules slow down, and the water gains thermal energy which causes its molecules to move more rapidly.