What does the activation energy for a chemical reaction mean? A. Energy of motion B. Stored energy C. Energy required to make the molecules collide so that a reaction may occur

answer is option C

Explanation:

i.e.

energy required to make the molecules collide so that reaction can occur.

option D. The rearrangement of particles in a physical change.

Explanation:

1) The change occured when a liquid substance becomes a solid is named freezing.

Yes, such as when liquid water becomes ice.

2) Such change is a change of phase or physical state of the matter. As such it is just a physical change: the chemical composition of the substance and the chemical bonds do not change.

3) At atomic or molecular level, what happens with the particles during freezing is that they come closer and are arranged in fixed positons one respect to the each other, so the particles do not slide over others. By occupying a fixed position, the substance acquires a definite shape and volume, and is not able to flow.