An example of a chemical change is A) baking a cake. This process involves a chemical reaction where the ingredients undergo changes to form new substances, such as the transformation of batter into solid cake due to heat.
In contrast, blowing air into a balloon (B), leaving a cup of ice water outside on a hot day (C), and breaking a pencil in half (D) are all physical changes, as they do not result in the formation of new chemical substances.