* Mixture: A combination of two or more substances where each substance retains its own chemical identity. The substances are physically mixed, not chemically bonded.

* Compound: A substance formed when two or more elements chemically combine in a fixed ratio.

When you make chocolate milk, you're simply mixing chocolate powder (which contains cocoa solids, sugar, and other ingredients) with milk. The chocolate particles and milk components don't chemically change into a new substance. You can still separate the chocolate from the milk (although it's not easy).

Let me know if you'd like to learn more about mixtures or compounds!