Describe the difference between a hot cup of water and cold in terms of thermal energy.

If you had two cups of water, one filled with hot water and another with cold water, the cold water will retain more molecules. The compounds that make up hot and cold water are the same. One oxygen and two hydrogen atoms make up each molecule. The pace at which the molecules wobble about is the disparity between them.

Explanation:

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds