How do matter, element, atom, crystal, compound, and molecule, relate?

They're all intertwined! For instance: Matter is composed of Atoms - which are kept together and create molecules.  Elements are made up of only one kind of atoms.  Atoms that have different elements and are bonded together form compounds. If atoms are ever aligned in a perfect 3d arrangement, they form an awesome crystal.

So in short: They all are one big happy family, so to speak that are either the outcome or help decide the outcome of the product.

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.