Which beaker has the least thermal energy? please don't guess, i already got 1 question wrong, i dont want a 60 on this.

It's B. beaker A

Explanation:

The thermal energy is directly proportional to to the mass of the solution times the temperature difference

In other words more mass and temperature means more thermal energy

So less mass (or mL of solution in our case) and less temperature means less energy

This means we choose the beaker A

Hope this helps have a good day

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.