Here's why:

* Compound: A compound is formed when two or more elements chemically combine in a fixed ratio. For example, water (H₂O) is a compound because it's always made up of two hydrogen atoms and one oxygen atom.

* Mixture: A mixture is a combination of two or more substances where each substance retains its own properties.

Baking powder is a mixture of:

* Sodium bicarbonate (NaHCO₃) - the primary leavening agent

* Acid: Usually a weak acid like tartaric acid, cream of tartar, or monocalcium phosphate. This reacts with the bicarbonate to produce carbon dioxide.

* Starch: Added to absorb moisture and prevent clumping.

The ingredients in baking powder are not chemically bonded, they are simply mixed together.