The molecules move at a faster rate. The molecules become more massive. The molecules expand and become wider. The molecules separate into atoms of hydrogen and oxygen.
I gave my students this multiple choice question: Anita heats a beaker containing water. As the temperature of the water increases, which change to the water molecules occurs?

Only one answer is correct among these 4 choices:
- The molecules move at a faster rate.
- The molecules become more massive.
- The molecules expand and become wider.
- The molecules separate into atoms of hydrogen and oxygen.

Could you tell me which one is correct?

The molecules move at a faster rate.