Question

a student drew this molecular model to represent liquid water at 10°c. how should the student change the model to best represent the water at 20°c? a) show the water molecules packed more tightly together. b) show some of the chemical bonds in the water molecules breaking. c) show some of the water molecules forming chemical bonds with each other. d) show the water molecules with longer arrows to represent an increase in motion.

Explanation:

As temperature increases from 10°C to 20°C, the kinetic energy of water molecules increases, leading to more motion. In a molecular - model representation, this is shown by longer arrows representing the motion of the molecules. Chemical bonds within water molecules do not break with a small temperature increase like this, and water molecules do not pack more tightly together as temperature rises in the liquid state. Also, the model is not showing bond - formation between water molecules at this temperature change.

Answer:

D) Show the water molecules with longer arrows to represent an increase in motion.