chemical reactions in the kitchen
Baking soda and vinegar create carbon dioxide. In both of these cases, a chemical reaction between a solid and liquid creates a new substance, a gas. Both yeast and baking soda can be used to create a gas.
chemical reactions in living things
when you hard boil an egg, the hydrogen sulfide produced by heating the egg white can react with iron from the egg yolk to form a grayish-green ring around the yolk.