A chemical reaction takes place when bread is baked.
When bread is baked, several chemical changes occur: yeast ferments the sugars in the dough, producing carbon dioxide gas and alcohol, which helps the bread rise and gives it texture. Additionally, the heat causes proteins and sugars to undergo Maillard reactions, leading to browning and the development of complex flavors.
In contrast, cooking rice primarily involves physical changes, such as the absorption of water and the gelatinization of starches, rather than significant chemical reactions.