Answer:
A. The liquid propane in a gas grill burns in a flame.
Explanation:
Chemical changes is the change which occur when the substance combines with the another to form a completely new substance.
Considering Options B, C and D, the identity of each specie is not changed but the state is changed and thus, these are physical changes.
On the other hand, Option A, when propane is being burnt in the flame , it changes to gas and its identity is lost. Thus, is a chemical change.
