If the Titan lake froze, how would the change in kinetic energy attect the speed of the more found in the lake?

The speed of the molecules in the lake will decrease due to decrease in the kinetic energy.

Kinetic energy is the energy due to the motion of particles.

Kinetic energy increases with increase in temperature.

Since the temperature of the lake decreases ad it freezes, the kinetic energy decrease and the speed of the molecules in the lake will decrease.

Learn more about Kinetic energy at: link

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

i believe that it is a exoplanet