What is an example of a chemical reaction taking place in a cooking recipe?

Question

What are some examples of chemical reactions taking place in a recipe...ex. brownie recipe or something?

Answer 1

Butter, when at the proper temperature (room temperature) when creamed with sugar as in making a cake will work much better than if the butter is cold or too warm (to tell if butter is the proper temperature, unwrap a stick and try to break it in half. If it is room temp it will bend)

Baking soda or baking powder can work as a leavening agent such as in brownies.

Check out Cooks.com for some very good info on chemical reactions in the kitchen.