A great example of an endothermic chemical change is the dissolving of ammonium chloride (NH₄Cl) in water.

Here's why:

* Endothermic: The process absorbs heat from the surroundings. You'll notice the solution feels cold to the touch because it's taking heat energy from your hand.

* Chemical Change: The ammonium chloride crystals are breaking apart and dissolving into ammonium ions (NH₄⁺) and chloride ions (Cl^-). This is a change in the chemical composition of the substance.

Here's a simple demonstration:

1. Materials: Ammonium chloride (NH₄Cl) crystals, water, a small beaker or container.

2. Procedure:

* Place a small amount of ammonium chloride crystals in the beaker.

* Add a small amount of water.

* Stir gently and observe the temperature change.

3. Observation: The solution will feel cold, indicating the reaction is endothermic.

This is just one example, but there are many other endothermic chemical changes.